question_answer 1)
A proton moving with a constant velocity passes through a region of space without any change in its velocity. If \[\overrightarrow{E}\] and \[\overrightarrow{B}\] represent the electric and magnetic fields respectively, then this region of space may have [IIT-JEE 1985; AMU 1995; AFMC 2001; Roorkee 2000; AMU (Med.) 2000]
A)
\[E=0,\,B=0\] done
clear
B)
\[E=0,\,B\ne 0\] done
clear
C)
\[E\ne 0,\,B=0\] done
clear
D)
\[E\ne 0,\,B\ne 0\] done
clear
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question_answer 2)
A uniform electric field and a uniform magnetic field are produced, pointed in the same direction. An electron is projected with its velocity pointing in the same direction [NCERT 1980; CBSE PMT 1993; JIPMER 1997; AIEEE 2005]
A)
The electron will turn to its right done
clear
B)
The electron will turn to its left done
clear
C)
The electron velocity will increase in magnitude done
clear
D)
The electron velocity will decrease in magnitude done
clear
View Solution play_arrow
question_answer 3)
Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describes circular path of radius \[{{R}_{1}}\] and \[{{R}_{2}}\] respectively. The ratio of mass of X to that of Y is [IIT-JEE 1988; CBSE PMT1995; MP PMT 2001]
A)
\[{{\left( \frac{{{R}_{1}}}{{{R}_{2}}} \right)}^{1/2}}\] done
clear
B)
\[\frac{{{R}_{2}}}{{{R}_{1}}}\] done
clear
C)
\[{{\left( \frac{{{R}_{1}}}{{{R}_{2}}} \right)}^{2}}\] done
clear
D)
\[\frac{{{R}_{1}}}{{{R}_{2}}}\] done
clear
View Solution play_arrow
question_answer 4)
A beam of ions with velocity \[2\times {{10}^{5}}\,m/s\] enters normally into a uniform magnetic field of \[4\times {{10}^{-2}}\,tesla\]. If the specific charge of the ion is \[5\times {{10}^{7}}\,C/kg\], then the radius of the circular path described will be [NCERT 1983; BVP 2003]
A)
0.10 m done
clear
B)
0.16 m done
clear
C)
0.20 m done
clear
D)
0.25 m done
clear
View Solution play_arrow
question_answer 5)
The radius of curvature of the path of the charged particle in a uniform magnetic field is directly proportional to [MNR 1995; UPSEAT 1999, 2000]
A)
The charge on the particle done
clear
B)
The momentum of the particle done
clear
C)
The energy of the particle done
clear
D)
The intensity of the field done
clear
View Solution play_arrow
question_answer 6)
An electron has mass \[9\times {{10}^{-31}}\,kg\] and charge \[1.6\times {{10}^{-19}}C\] is moving with a velocity of \[{{10}^{6}}\,m/s\], enters a region where magnetic field exists. If it describes a circle of radius 0.10 m, the intensity of magnetic field must be [NCERT 1982; CPMT 1989; DCE 2005]
A)
\[1.8\times {{10}^{-4}}\,T\] done
clear
B)
\[5.6\times {{10}^{-5}}\,T\] done
clear
C)
\[14.4\times {{10}^{-5}}\,T\] done
clear
D)
\[1.3\times {{10}^{-6}}\,T\] done
clear
View Solution play_arrow
question_answer 7)
A proton (mass m and charge +e) and an \[\alpha -\]particle (mass 4m and charge +2e) are projected with the same kinetic energy at right angles to the uniform magnetic field. Which one of the following statements will be true [NCERT 1983]
A)
The \[\alpha -\]particle will be bent in a circular path with a small radius that for the proton done
clear
B)
The radius of the path of the \[\alpha -\]particle will be greater than that of the proton done
clear
C)
The \[\alpha -\]particle and the proton will be bent in a circular path with the same radius done
clear
D)
The \[\alpha -\]particle and the proton will go through the field in a straight line done
clear
View Solution play_arrow
question_answer 8)
A charged particle moving in a magnetic field experiences a resultant force [MP PMT 1994]
A)
In the direction of field done
clear
B)
In the direction opposite to that field done
clear
C)
In the direction perpendicular to both the field and its velocity done
clear
D)
None of the above done
clear
View Solution play_arrow
question_answer 9)
If the direction of the initial velocity of the charged particle is perpendicular to the magnetic field, then the orbit will be or The path executed by a charged particle whose motion is perpendicular to magnetic field is [MP PMT 1993; CPMT 1996]
A)
A straight line done
clear
B)
An ellipse done
clear
C)
A circle done
clear
D)
A helix done
clear
View Solution play_arrow
question_answer 10)
If the direction of the initial velocity of the charged particle is neither along nor perpendicular to that of the magnetic field, then the orbit will be [MP PET 1993]
A)
A straight line done
clear
B)
An ellipse done
clear
C)
A circle done
clear
D)
A helix done
clear
View Solution play_arrow
question_answer 11)
Particles having positive charges occasionally come with high velocity from the sky towards the earth. On account of the magnetic field of earth, they would be deflected towards the [NCERT 1977]
A)
North done
clear
B)
South done
clear
C)
East done
clear
D)
West done
clear
View Solution play_arrow
question_answer 12)
A 2 MeV proton is moving perpendicular to a uniform magnetic field of 2.5 tesla. The force on the proton is [CPMT 1989]
A)
\[2.5\times {{10}^{-10}}\,N\] done
clear
B)
\[7.6\times {{10}^{-11}}\,N\] done
clear
C)
\[2.5\times {{10}^{-11}}\,N\] done
clear
D)
\[7.6\times {{10}^{-12}}\,N\] done
clear
View Solution play_arrow
question_answer 13)
A charged particle moves with velocity v in a uniform magnetic field \[\overrightarrow{B}\]. The magnetic force experienced by the particle is [CBSE PMT 1990]
A)
Always zero done
clear
B)
Never zero done
clear
C)
Zero, if \[\overrightarrow{B}\] and \[\overrightarrow{v\,}\] are perpendicular done
clear
D)
Zero, if \[\overrightarrow{B}\] and \[\overrightarrow{v\,}\] are parallel done
clear
View Solution play_arrow
question_answer 14)
A proton is moving along Z-axis in a magnetic field. The magnetic field is along X-axis. The proton will experience a force along
A)
X-axis done
clear
B)
Y-axis done
clear
C)
Z-axis done
clear
D)
Negative Z-axis done
clear
View Solution play_arrow
question_answer 15)
A proton of mass m and charge +e is moving in a circular orbit in a magnetic field with energy 1 MeV. What should be the energy of \[\alpha -\]particle (mass = 4m and charge = + 2e), so that it can revolve in the path of same radius [BHU 1997]
A)
1 MeV done
clear
B)
4 MeV done
clear
C)
2 MeV done
clear
D)
0.5 MeV done
clear
View Solution play_arrow
question_answer 16)
An electron is moving with a speed of \[{{10}^{8}}\,m/\sec \] perpendicular to a uniform magnetic field of intensity B. Suddenly intensity of the magnetic field is reduced to B/2. The radius of the path becomes from the original value of r [MP PET 1993]
A)
No change done
clear
B)
Reduces to r / 2 done
clear
C)
Increases to 2r done
clear
D)
Stops moving done
clear
View Solution play_arrow
question_answer 17)
A proton and an \[\alpha -\]particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25 \[\mu \] sec to make 5 revolutions, then the periodic time for the \[\alpha -\]particle would be [MP PET 1993]
A)
50 \[\mu \] sec done
clear
B)
25 \[\mu \] sec done
clear
C)
10 \[\mu \] sec done
clear
D)
5 \[\mu \] sec done
clear
View Solution play_arrow
question_answer 18)
A proton (mass \[=1.67\times {{10}^{-27}}\,kg\] and charge \[=1.6\times {{10}^{-19}}\,C)\] enters perpendicular to a magnetic field of intensity 2 \[weber/{{m}^{2}}\] with a velocity \[3.4\times {{10}^{7}}\,m/\sec \]. The acceleration of the proton should be [DPMT 1999]
A)
\[6.5\times {{10}^{15}}\,m/{{\sec }^{2}}\] done
clear
B)
\[6.5\times {{10}^{13}}\,m/{{\sec }^{2}}\] done
clear
C)
\[6.5\times {{10}^{11}}\,m/{{\sec }^{2}}\] done
clear
D)
\[6.5\times {{10}^{9}}\,m/{{\sec }^{2}}\] done
clear
View Solution play_arrow
question_answer 19)
An \[\alpha -\]particle travels in a circular path of radius 0.45 m in a magnetic field \[B=1.2\,Wb/{{m}^{2}}\] with a speed of \[2.6\times {{10}^{7}}\,m/\sec \]. The period of revolution of the \[\alpha -\]particle is
A)
\[1.1\times {{10}^{-5}}\,\sec \] done
clear
B)
\[1.1\times {{10}^{-6}}\sec \] done
clear
C)
\[1.1\times {{10}^{-7}}\,\sec \] done
clear
D)
\[1.1\times {{10}^{-8}}\,\sec \] done
clear
View Solution play_arrow
question_answer 20)
A uniform magnetic field B is acting from south to north and is of magnitude 1.5 \[Wb/{{m}^{2}}\]. If a proton having mass \[=1.7\times {{10}^{-27}}\,kg\] and charge \[=1.6\times {{10}^{-19}}\,C\] moves in this field vertically downwards with energy 5 MeV, then the force acting on it will be [Pb. PMT 2002]
A)
\[7.4\times {{10}^{12}}\,N\] done
clear
B)
\[7.4\times {{10}^{-12}}\,N\] done
clear
C)
\[7.4\times {{10}^{19}}\,N\] done
clear
D)
\[7.4\times {{10}^{-19}}\,N\] done
clear
View Solution play_arrow
question_answer 21)
A strong magnetic field is applied on a stationary electron, then [BIT 1989; MP PMT 1995; CPMT 1999]
A)
The electron moves in the direction of the field done
clear
B)
The electron moves in an opposite direction done
clear
C)
The electron remains stationary done
clear
D)
The electron starts spinning done
clear
View Solution play_arrow
question_answer 22)
A uniform magnetic field acts at right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of the electrons is doubled, then the radius of the circular path will be [CBSE PMT 1991]
A)
2.0 cm done
clear
B)
0.5 cm done
clear
C)
4.0 cm done
clear
D)
1.0 cm done
clear
View Solution play_arrow
question_answer 23)
A deutron of kinetic energy 50 keV is describing a circular orbit of radius 0.5 metre in a plane perpendicular to magnetic field \[\overrightarrow{B}\]. The kinetic energy of the proton that describes a circular orbit of radius 0.5 metre in the same plane with the same \[\overrightarrow{B}\] is [CBSE PMT 1991]
A)
25 keV done
clear
B)
50 keV done
clear
C)
200 keV done
clear
D)
100 keV done
clear
View Solution play_arrow
question_answer 24)
If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity v and an electron is projected along the lines of force, what will happen to proton and electron [DPMT 1979]
A)
The electron will travel along a circle with constant speed and the proton will move along a straight line done
clear
B)
Proton will move in a circle with constant speed and there will be no effect on the motion of electron done
clear
C)
There will not be any effect on the motion of electron and proton done
clear
D)
The electron and proton both will follow the path of a parabola done
clear
View Solution play_arrow
question_answer 25)
An electron is travelling horizontally towards east. A magnetic field in vertically downward direction exerts a force on the electron along [EAMCET 1984]
A)
East done
clear
B)
West done
clear
C)
North done
clear
D)
South done
clear
View Solution play_arrow
question_answer 26)
Lorentz force can be calculated by using the formula [MP PET 1994, 2002, 03; CBSE PMT 2002]
A)
\[\overrightarrow{F}=q\,(\overrightarrow{E}+\overrightarrow{v}\times \overrightarrow{B})\] done
clear
B)
\[\overrightarrow{F}=q\,(\overrightarrow{E}-\overrightarrow{v}\times \overrightarrow{B})\] done
clear
C)
\[\overrightarrow{F}=q\,(\overrightarrow{E}+\overrightarrow{v}\cdot \overrightarrow{B})\] done
clear
D)
\[\overrightarrow{F}=q\,(\overrightarrow{E}\times \overrightarrow{B}+\overrightarrow{v})\] done
clear
View Solution play_arrow
question_answer 27)
A magnetic field [MP PET 1994; Pb PMT 2003]
A)
Always exerts a force on a charged particle done
clear
B)
Never exerts a force on a charged particle done
clear
C)
Exerts a force, if the charged particle is moving across the magnetic field lines done
clear
D)
Exerts a force, if the charged particle is moving along the magnetic field lines done
clear
View Solution play_arrow
question_answer 28)
A proton enters a magnetic field of flux density \[1.5\,weber/{{m}^{2}}\] with a velocity of \[2\times {{10}^{7}}\,m/\sec \] at an angle of \[30{}^\circ \] with the field. The force on the proton will be [MP PET 1994 ; Pb. PMT 2004]
A)
\[2.4\times {{10}^{-12}}\,N\] done
clear
B)
\[0.24\times {{10}^{-12}}\,N\] done
clear
C)
\[24\times {{10}^{-12}}\,N\] done
clear
D)
\[0.024\times {{10}^{-12}}\,N\] done
clear
View Solution play_arrow
question_answer 29)
If a particle of charge \[{{10}^{-12}}\,coulomb\] moving along the \[\hat{x}-\]direction with a velocity \[{{10}^{5}}\,m/s\] experiences a force of \[{{10}^{-10}}\,newton\] in \[\hat{y}-\]direction due to magnetic field, then the minimum magnetic field is [MP PMT 1994]
A)
\[6.25\times {{10}^{3}}\,tesla\] in \[\hat{z}-\]direction done
clear
B)
\[{{10}^{-15}}\,tesla\] in \[\hat{z}-\]direction done
clear
C)
\[6.25\times {{10}^{-3}}\,tesla\] in \[\hat{z}-\]direction done
clear
D)
\[{{10}^{-3}}\,tesla\] in \[\hat{z}-\]direction done
clear
View Solution play_arrow
question_answer 30)
If a proton, deutron and \[\alpha -\]particle on being accelerated by the same potential difference enters perpendicular to the magnetic field, then the ratio of their kinetic energies is [MP PMT 2003; J & K CET 2005]
A)
1 : 2 : 2 done
clear
B)
2 : 2 : 1 done
clear
C)
1 : 2 : 1 done
clear
D)
1 : 1 : 2 done
clear
View Solution play_arrow
question_answer 31)
Which of the following statement is true [Manipal MEE 1995]
A)
The presence of a large magnetic flux through a coil maintains a current in the coil if the circuit is continuous done
clear
B)
A coil of a metal wire kept stationary in a non-uniform magnetic field has an e.m.f. induced in it done
clear
C)
A charged particle enters a region of uniform magnetic field at an angle of \[85{}^\circ \] to the magnetic lines of force; the path of the particle is a circle done
clear
D)
There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it done
clear
View Solution play_arrow
question_answer 32)
An electron and a proton enter region of uniform magnetic field in a direction at right angles to the field with the same kinetic energy. They describe circular paths of radius \[{{r}_{e}}\] and \[{{r}_{p}}\] respectively. Then [Manipal MEE 1995]
A)
\[{{r}_{e}}={{r}_{p}}\] done
clear
B)
\[{{r}_{e}}<{{r}_{p}}\] done
clear
C)
\[{{r}_{e}}>{{r}_{p}}\] done
clear
D)
\[{{r}_{e}}\] may be less than or greater than \[{{r}_{p}}\] depending on the direction of the magnetic field done
clear
View Solution play_arrow
question_answer 33)
A proton of mass \[1.67\times {{10}^{-27}}kg\] and charge \[1.6\times {{10}^{-19}}\,C\] is projected with a speed of \[2\times {{10}^{6}}\,m/s\] at an angle of \[60{}^\circ \] to the \[X-\]axis. If a uniform magnetic field of 0.104 Tesla is applied along \[Y-\]axis, the path of proton is [IIT-JEE 1995]
A)
A circle of radius = 0.2 m and time period \[\pi \times {{10}^{-7}}s\] done
clear
B)
A circle of radius = 0.1 m and time period \[2\pi \times {{10}^{-7}}s\] done
clear
C)
A helix of radius = 0.1 m and time period \[2\pi \times {{10}^{-7}}s\] done
clear
D)
A helix of radius = 0.2 m and time period \[4\pi \times {{10}^{-7}}s\] done
clear
View Solution play_arrow
question_answer 34)
A proton and a deutron both having the same kinetic energy, enter perpendicularly into a uniform magnetic field B. For motion of proton and deutron on circular path of radius \[{{R}_{p}}\] and \[{{R}_{d}}\] respectively, the correct statement is [MP PET 1995]
A)
\[{{R}_{d}}=\sqrt{2}\,{{R}_{p}}\] done
clear
B)
\[{{R}_{d}}={{R}_{p}}/\sqrt{2}\] done
clear
C)
\[{{R}_{d}}={{R}_{p}}\] done
clear
D)
\[{{R}_{d}}=2{{R}_{p}}\] done
clear
View Solution play_arrow
question_answer 35)
A proton (or charged particle) moving with velocity v is acted upon by electric field E and magnetic field B. The proton will move undeflected if [MP PMT 1995, 2003; UPSEAT 2002; DPMT 2003]
A)
E is perpendicular to B done
clear
B)
E is parallel to v and perpendicular to B done
clear
C)
E, B and v are mutually perpendicular and \[v=\frac{E}{B}\] done
clear
D)
E and B both are parallel to v done
clear
View Solution play_arrow
question_answer 36)
A proton and an electron both moving with the same velocity v enter into a region of magnetic field directed perpendicular to the velocity of the particles. They will now move in circular orbits such that [MP PMT 1995]
A)
Their time periods will be same done
clear
B)
The time period for proton will be higher done
clear
C)
The time period for electron will be higher done
clear
D)
Their orbital radii will be same done
clear
View Solution play_arrow
question_answer 37)
A charge + Q is moving upwards vertically. It enters a magnetic field directed to the north. The force on the charge will be towards [MP PMT 1995; AMU (Engg.) 2000]
A)
North done
clear
B)
South done
clear
C)
East done
clear
D)
West done
clear
View Solution play_arrow
question_answer 38)
An electron is moving on a circular path of radius r with speed v in a transverse magnetic field B. e/m for it will be [MP PMT 2003]
A)
\[\frac{v}{Br}\] done
clear
B)
\[\frac{B}{rv}\] done
clear
C)
Bvr done
clear
D)
\[\frac{vr}{B}\] done
clear
View Solution play_arrow
question_answer 39)
A beam of well collimated cathode rays travelling with a speed of \[5\times {{10}^{6}}\,m{{s}^{-1}}\] enter a region of mutually perpendicular electric and magnetic fields and emerge undeviated from this region. If \[|B|\,=0.02\,T\], the magnitude of the electric field is [Haryana CEE 1996]
A)
\[{{10}^{5}}\,V{{m}^{-1}}\] done
clear
B)
\[2.5\times {{10}^{8}}\,V{{m}^{-1}}\] done
clear
C)
\[1.25\times {{10}^{10}}\,V{{m}^{-1}}\] done
clear
D)
\[2\times {{10}^{3}}\,V{{m}^{-1}}\] done
clear
View Solution play_arrow
question_answer 40)
An electron having charge \[1.6\times {{10}^{-19}}\,C\] and mass \[9\times {{10}^{-31}}\,kg\] is moving with \[4\times {{10}^{6}}\,m{{s}^{-1}}\] speed in a magnetic field \[2\times {{10}^{-1}}\,tesla\] in a circular orbit. The force acting on electron and the radius of the circular orbit will be [MP PET 1996; JIPMER 2000; BVP 2003]
A)
\[12.8\times {{10}^{-13}}N,\,1.1\times {{10}^{-4}}m\] done
clear
B)
\[1.28\times {{10}^{-14}}N,\,1.1\times {{10}^{-3}}m\] done
clear
C)
\[1.28\times {{10}^{-13}}N,\,1.1\times {{10}^{-3}}m\] done
clear
D)
\[1.28\times {{10}^{-13}}N,\,1.1\times {{10}^{-4}}m\] done
clear
View Solution play_arrow
question_answer 41)
An electron enters a magnetic field whose direction is perpendicular to the velocity of the electron. Then [MP PMT 1996; CBSE PMT 2003]
A)
The speed of the electron will increase done
clear
B)
The speed of the electron will decrease done
clear
C)
The speed of the electron will remain the same done
clear
D)
The velocity of the electron will remain the same done
clear
View Solution play_arrow
question_answer 42)
An electron is moving in the north direction. It experiences a force in vertically upward direction. The magnetic field at the position of the electron is in the direction of [MP PET 2003]
A)
East done
clear
B)
West done
clear
C)
North done
clear
D)
South done
clear
View Solution play_arrow
question_answer 43)
A current carrying long solenoid is placed on the ground with its axis vertical. A proton is falling along the axis of the solenoid with a velocity v. When the proton enters into the solenoid, it will
A)
Be deflected from its path done
clear
B)
Be accelerated along the same path done
clear
C)
Be decelerated along the same path done
clear
D)
Move along the same path with no change in velocity done
clear
View Solution play_arrow
question_answer 44)
A charged particle of mass m and charge q describes circular motion of radius r in a uniform magnetic field of strength B. The frequency of revolution is [MP PET 1997; RPET 2001]
A)
\[\frac{Bq}{2\pi m}\] done
clear
B)
\[\frac{Bq}{2\pi rm}\] done
clear
C)
\[\frac{2\pi m}{Bq}\] done
clear
D)
\[\frac{Bm}{2\pi q}\] done
clear
View Solution play_arrow
question_answer 45)
An electron is accelerated by a potential difference of 12000 volts. It then enters a uniform magnetic field of \[{{10}^{-3}}\,T\] applied perpendicular to the path of electron. Find the radius of path. Given mass of electron \[=9\times {{10}^{-31}}\,kg\] and charge on electron \[=1.6\times {{10}^{-19}}\,C\] [MP PET 1997]
A)
36.7 m done
clear
B)
36.7 cm done
clear
C)
3.67 m done
clear
D)
3.67 cm done
clear
View Solution play_arrow
question_answer 46)
-The charge on a particle Y is double the charge on particle X. These two particles X and Y after being accelerated through the same potential difference enter a region of uniform magnetic field and describe circular paths of radii \[{{R}_{1}}\] and \[{{R}_{2}}\] respectively. The ratio of the mass of X to that of Y is [MP PET 1997]
A)
\[{{\left( \frac{2{{R}_{1}}}{{{R}_{2}}} \right)}^{2}}\] done
clear
B)
\[{{\left( \frac{{{R}_{1}}}{2{{R}_{2}}} \right)}^{2}}\] done
clear
C)
\[\frac{R_{1}^{2}}{2R_{2}^{2}}\] done
clear
D)
\[\frac{2{{R}_{1}}}{{{R}_{2}}}\] done
clear
View Solution play_arrow
question_answer 47)
A particle with \[{{10}^{-11}}\,coulomb\] of charge and \[{{10}^{-7}}\,kg\] mass is moving with a velocity of \[{{10}^{8}}\,m/s\] along the y-axis. A uniform static magnetic field \[B=0.5\,Tesla\] is acting along the x-direction. The force on the particle is [MP PMT 1997]
A)
\[5\times {{10}^{-11}}\,N\] along \[\hat{i}\] done
clear
B)
\[5\times {{10}^{3}}\] N along \[\hat{k}\] done
clear
C)
\[5\times {{10}^{-11}}\,N\] along \[-\hat{j}\] done
clear
D)
\[5\times {{10}^{-4}}\,N\] along \[-\hat{k}\] done
clear
View Solution play_arrow
question_answer 48)
A particle of charge q and mass m moving with a velocity v along the x-axis enters the region x > 0 with uniform magnetic field B along the \[\hat{k}\] direction. The particle will penetrate in this region in the x-direction upto a distance d equal to [MP PMT 1997]
A)
Zero done
clear
B)
\[\frac{mv}{qB}\] done
clear
C)
\[\frac{2mv}{qB}\] done
clear
D)
Infinity done
clear
View Solution play_arrow
question_answer 49)
A charged particle is moving with velocity v in a magnetic field of induction B. The force on the particle will be maximum when [MP PMT/PET 1998]
A)
v and B are in the same direction done
clear
B)
v and B are in opposite directions done
clear
C)
v and B are perpendicular done
clear
D)
v and B are at an angle of \[45{}^\circ \] done
clear
View Solution play_arrow
question_answer 50)
A charged particle enters a magnetic field H with its initial velocity making an angle of \[45{}^\circ \] with H. The path of the particle will be [MP PET 1999; AIIMS 1999; BHU 1999]
A)
A straight line done
clear
B)
A circle done
clear
C)
An ellipse done
clear
D)
A helix done
clear
View Solution play_arrow
question_answer 51)
An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true [MP PET 1999]
A)
Trajectory of electron is less curved done
clear
B)
Trajectory of proton is less curved done
clear
C)
Both trajectories are equally curved done
clear
D)
Both move on straight-line path done
clear
View Solution play_arrow
question_answer 52)
A charged particle moves in a uniform magnetic field. The velocity of the particle at some instant makes an acute angle with the magnetic field. The path of the particle will be [MP PMT 1999]
A)
A straight line done
clear
B)
A circle done
clear
C)
A helix with uniform pitch done
clear
D)
A helix with non-uniform pitch done
clear
View Solution play_arrow
question_answer 53)
An electron is moving along positive x-axis. To get it moving on an anticlockwise circular path in x-y plane, a magnetic filed is applied [MP PMT 1999]
A)
Along positive y-axis done
clear
B)
Along positive z-axis done
clear
C)
Along negative y-axis done
clear
D)
Along negative z-axis done
clear
View Solution play_arrow
question_answer 54)
A moving charge will gain energy due to the application of [CPMT 1999]
A)
Electric field done
clear
B)
Magnetic field done
clear
C)
Both of these done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 55)
A proton, a deuteron and an \[\alpha -\]particle having the same kinetic energy are moving in circular trajectories in a constant magnetic field. If \[{{r}_{p}},\,{{r}_{d}}\] and \[{{r}_{\alpha }}\] denote respectively the radii of the trajectories of these particles, then [IIT 1997 Re-Exam]
A)
\[{{r}_{\alpha }}={{r}_{p}}<{{r}_{d}}\] done
clear
B)
\[{{r}_{\alpha }}>{{r}_{d}}>{{r}_{p}}\] done
clear
C)
\[{{r}_{\alpha }}={{r}_{d}}>{{r}_{p}}\] done
clear
D)
\[{{r}_{p}}={{r}_{d}}={{r}_{\alpha }}\] done
clear
View Solution play_arrow
question_answer 56)
When a magnetic field is applied in a direction perpendicular to the direction of cathode rays, then their [EAMCET 1994; BHU 2005]
A)
Energy decreases done
clear
B)
Energy increases done
clear
C)
Momentum increases done
clear
D)
Momentum and energy remain unchanged done
clear
View Solution play_arrow
question_answer 57)
A charge moves in a circle perpendicular to a magnetic field. The time period of revolution is independent of [RPET 1997; AIEEE 2002]
A)
Magnetic field done
clear
B)
Charge done
clear
C)
Mass of the particle done
clear
D)
Velocity of the particle done
clear
View Solution play_arrow
question_answer 58)
A proton of energy 200 MeV enters the magnetic field of 5 T. If direction of field is from south to north and motion is upward, the force acting on it will be [RPET 1997]
A)
Zero done
clear
B)
\[1.6\times {{10}^{-10}}N\] done
clear
C)
\[3.2\times {{10}^{-8}}N\] done
clear
D)
\[1.6\times {{10}^{-6}}N\] done
clear
View Solution play_arrow
question_answer 59)
An electron enters a region where magnetic and electric (E) fields are mutually perpendicular to one another, then [CBSE PMT1993]
A)
It will always move in the direction of B done
clear
B)
It will always move in the direction of E done
clear
C)
It always possess circular motion done
clear
D)
It can go undeflected also done
clear
View Solution play_arrow
question_answer 60)
A charge moving with velocity v in X-direction is subjected to a field of magnetic induction in the negative X-direction. As a result, the charge will [CBSE PMT1993]
A)
Remain unaffected done
clear
B)
Start moving in a circular path Y-Z plane done
clear
C)
Retard along X-axis done
clear
D)
Move along a helical path around X-axis done
clear
View Solution play_arrow
question_answer 61)
An electron and a proton with equal momentum enter perpendicularly into a uniform magnetic field, then [BHU 1997; AIEEE 2002; MH CET (Med.) 2000]
A)
The path of proton shall be more curved than that of electron done
clear
B)
The path of proton shall be less curved than that of electron done
clear
C)
Both are equally curved done
clear
D)
Path of both will be straight line done
clear
View Solution play_arrow
question_answer 62)
A positively charged particle moving due east enters a region of uniform magnetic field directed vertically upwards. The particle will [CBSE PMT 1997]
A)
Get deflected vertically upwards done
clear
B)
Move in a circular orbit with its speed increased done
clear
C)
Move in a circular orbit with its speed unchanged done
clear
D)
Continue to move due east done
clear
View Solution play_arrow
question_answer 63)
A particle moving in a magnetic field increases its velocity, then its radius of the circle [BHU 1998]
A)
Decreases done
clear
B)
Increases done
clear
C)
Remains the same done
clear
D)
Becomes half done
clear
View Solution play_arrow
question_answer 64)
A particle is moving in a uniform magnetic field, then [BHU 1998]
A)
Its momentum changes but total energy remains the same done
clear
B)
Both momentum and total energy remain the same done
clear
C)
Both will change done
clear
D)
Total energy changes but momentum remains the same done
clear
View Solution play_arrow
question_answer 65)
If an electron is going in the direction of magnetic field \[\overrightarrow{B}\] with the velocity of \[\overrightarrow{v\,}\] then the force on electron is [RPMT 1999]
A)
Zero done
clear
B)
\[e\,(\overrightarrow{v\,}\cdot \overrightarrow{B})\] done
clear
C)
\[e\,(\overrightarrow{v\,}\times \overrightarrow{B})\] done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 66)
One proton beam enters a magnetic field of \[{{10}^{-4}}\]T normally, Specific charge = \[{{10}^{11}}\,C/kg.\] velocity = \[{{10}^{7}}\,m/s\]. What is the radius of the circle described by it [DCE 1999]
A)
0.1 m done
clear
B)
1 m done
clear
C)
10 m done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 67)
In a cyclotron, the angular frequency of a charged particle is independent of [CPMT 1999]
A)
Mass done
clear
B)
Speed done
clear
C)
Charge done
clear
D)
Magnetic field done
clear
View Solution play_arrow
question_answer 68)
A charged particle is moving in a uniform magnetic field in a circular path. Radius of circular path is R. When energy of particle is doubled, then new radius will be [CPMT 1999; Pb. PET 2002]
A)
\[R\sqrt{2}\] done
clear
B)
\[R\sqrt{3}\] done
clear
C)
2 R done
clear
D)
3 R done
clear
View Solution play_arrow
question_answer 69)
The radius of curvature of the path of a charged particle moving in a static uniform magnetic field is [Roorkee 1999]
A)
Directly proportional to the magnitude of the charge on the particle done
clear
B)
Directly proportional to the magnitude of the linear momentum of the particle done
clear
C)
Directly proportional to the kinetic energy of the particle done
clear
D)
Inversely proportional to the magnitude of the magnetic field done
clear
View Solution play_arrow
question_answer 70)
A proton moving with a velocity, \[2.5\times {{10}^{7}}m/s\], enters a magnetic field of intensity 2.5T making an angle \[{{30}^{o}}\] with the magnetic field. The force on the proton is [AFMC 2000; CBSE PMT 2000]
A)
\[3\times {{10}^{-12}}N\] done
clear
B)
\[5\times {{10}^{-12}}N\] done
clear
C)
\[6\times {{10}^{-12}}\]N done
clear
D)
\[9\times {{10}^{-12}}N\] done
clear
View Solution play_arrow
question_answer 71)
Maximum kinetic energy of the positive ion in the cyclotron is [Pb. PMT 2000]
A)
\[\frac{{{q}^{2}}B{{r}_{0}}}{2m}\] done
clear
B)
\[\frac{q{{B}^{2}}{{r}_{o}}}{2m}\] done
clear
C)
\[\frac{{{q}^{2}}{{B}^{2}}r_{0}^{2}}{2m}\] done
clear
D)
\[\frac{qB{{r}_{0}}}{2{{m}^{2}}}\] done
clear
View Solution play_arrow
question_answer 72)
A charge q is moving in a magnetic field then the magnetic force does not depend upon [RPET 2000]
A)
Charge done
clear
B)
Mass done
clear
C)
Velocity done
clear
D)
Magnetic field done
clear
View Solution play_arrow
question_answer 73)
An electron is travelling in east direction and a magnetic field is applied in upward direction then electron will deflect in [RPET 2000]
A)
South done
clear
B)
North done
clear
C)
West done
clear
D)
East done
clear
View Solution play_arrow
question_answer 74)
A charge of 1C is moving in a magnetic field of 0.5Tesla with a velocity of 10m/sec Perpendicular to the field. Force experienced is [RPMT 2000]
A)
5 N done
clear
B)
10 N done
clear
C)
0.5 N done
clear
D)
0 N done
clear
View Solution play_arrow
question_answer 75)
An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform of magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of [Kerala PMT 2004; KCET 2000, 05]
A)
\[\frac{r}{4}\] done
clear
B)
\[\frac{r}{2}\] done
clear
C)
\[2r\] done
clear
D)
\[4r\] done
clear
View Solution play_arrow
question_answer 76)
If an electron enters a magnetic field with its velocity pointing in the same direction as the magnetic field, then [MP PMT 2000]
A)
The electron will turn to its right done
clear
B)
The electron will turn to its left done
clear
C)
The velocity of the electron will increase done
clear
D)
The velocity of the electron will remain unchanged done
clear
View Solution play_arrow
question_answer 77)
A particle of mass m and charge q enters a magnetic field B perpendicularly with a velocity v, The radius of the circular path described by it will be [MP PMT 2000]
A)
\[Bq/mv\] done
clear
B)
\[mq/Bv\] done
clear
C)
\[mB/qv\] done
clear
D)
\[mv/Bq\] done
clear
View Solution play_arrow
question_answer 78)
An electron moving towards the east enters a magnetic field directed towards the north. The force on the electron will be directed [MP PET 2000]
A)
Vertically upward done
clear
B)
Vertically downward done
clear
C)
Towards the west done
clear
D)
Towards the south done
clear
View Solution play_arrow
question_answer 79)
An electron (mass = 9.0×\[{{10}^{-31}}\]kg and charge =\[1.6\times {{10}^{-19}}\]coulomb) is moving in a circular orbit in a magnetic field of \[1.0\times {{10}^{-4}}\,weber/{{m}^{2}}.\] Its period of revolution is [MP PET 2000; Pb PET 2003]
A)
\[3.5\times {{10}^{-7}}\]sec done
clear
B)
\[7.0\times {{10}^{-7}}\]sec done
clear
C)
\[1.05\times {{10}^{-6}}\]sec done
clear
D)
\[2.1\times {{10}^{-6}}\]sec done
clear
View Solution play_arrow
question_answer 80)
An electron (charge q coulomb) enters a magnetic field of H \[weber/{{m}^{2}}\] with a velocity of \[v\,m/s\] in the same direction as that of the field the force on the electron is [MP PET 2000]
A)
Hqv Newton?s in the direction of the magnetic field done
clear
B)
Hqv dynes in the direction of the magnetic field done
clear
C)
Hqv Newton?s at right angles to the direction of the magnetic field done
clear
D)
Zero done
clear
View Solution play_arrow
question_answer 81)
A homogeneous electric field E and a uniform magnetic field \[\overset{\to }{\mathop{B}}\,\] are pointing in the same direction. A proton is projected with its velocity parallel to \[\overset{\to }{\mathop{E}}\,\]. It will [Roorkee 2000]
A)
Go on moving in the same direction with increasing velocity done
clear
B)
Go on moving in the same direction with constant velocity done
clear
C)
Turn to its right done
clear
D)
Turn to its left done
clear
View Solution play_arrow
question_answer 82)
The radius of circular path of an electron when subjected to a perpendicular magnetic field is [Pb. PMT 1999; DCE 2000; MH CET (Med.) 2000]
A)
\[\frac{mv}{Be}\] done
clear
B)
\[\frac{me}{Be}\] done
clear
C)
\[\frac{mE}{Be}\] done
clear
D)
\[\frac{Be}{mv}\] done
clear
View Solution play_arrow
question_answer 83)
Cyclotron is used to accelerate [AIIMS 2001; BCECE 2004]
A)
Electrons done
clear
B)
Neutrons done
clear
C)
Positive ions done
clear
D)
Negative ions done
clear
View Solution play_arrow
question_answer 84)
Two particles A and B of masses \[{{m}_{A}}\] and \[{{m}_{B}}\] respectively and having the same charge are moving in a plane. A uniform magnetic field exists perpendicular to this plane. The speeds of the particles are \[{{v}_{A}}\] and \[{{v}_{B}}\] respectively, and the trajectories are as shown in the figure. Then [IIT-JEE (Screening) 2001]
A)
\[{{m}_{A}}{{v}_{A}}<{{m}_{B}}{{v}_{B}}\] done
clear
B)
\[{{m}_{A}}{{v}_{A}}>{{m}_{B}}{{v}_{B}}\] done
clear
C)
\[{{m}_{A}}<{{m}_{B}}\,\,\text{and}\,\,{{v}_{A}}<{{v}_{B}}\] done
clear
D)
\[{{m}_{A}}=\,{{m}_{B}}\,\text{and }{{v}_{A}}={{v}_{B}}\] done
clear
View Solution play_arrow
question_answer 85)
A proton and an alpha particle are separately projected in a region where a uniform magnetic field exists. Their initial velocities are perpendicular to direction of magnetic field. If both the particles move around magnetic field in circles of equal radii, the ratio of momentum of proton to alpha particle \[\left( \frac{{{P}_{p}}}{{{P}_{\alpha }}} \right)\]is [MP PET 2001]
A)
1 done
clear
B)
\[\frac{1}{2}\] done
clear
C)
2 done
clear
D)
\[\frac{1}{4}\] done
clear
View Solution play_arrow
question_answer 86)
A particle of mass 0.6 g and having charge of 25 nC is moving horizontally with a uniform velocity \[\text{1}\text{.2}\times \text{1}{{\text{0}}^{\text{4}}}m{{s}^{-1}}\] in a uniform magnetic field, then the value of the magnetic induction is \[(g=10\,m{{s}^{-2}})\] [EAMCET 2001]
A)
Zero done
clear
B)
10 T done
clear
C)
20 T done
clear
D)
200 T done
clear
View Solution play_arrow
question_answer 87)
An \[\alpha \] particle and a proton travel with same velocity in a magnetic field perpendicular to the direction of their velocities, find the ratio of the radii of their circular path [AIIMS 2004; DCE 2001, 03; Kerala PMT 2005]
A)
4 : 1 done
clear
B)
1 : 4 done
clear
C)
2 : 1 done
clear
D)
1 : 2 done
clear
View Solution play_arrow
question_answer 88)
Motion of a moving electron is not affected by [AMU (Engg.) 2001]
A)
An electric field applied in the direction of motion done
clear
B)
Magnetic field applied in the direction of motion done
clear
C)
Electric field applied perpendicular to the direction of motion done
clear
D)
Magnetic field applied perpendicular to the direction of motion done
clear
View Solution play_arrow
question_answer 89)
When a charged particle enters a uniform magnetic field its kinetic energy [MP PMT 2001; MP PET 2002]
A)
Remains constant done
clear
B)
Increases done
clear
C)
Decreases done
clear
D)
Becomes zero done
clear
View Solution play_arrow
question_answer 90)
If cathode rays are projected at right angles to a magnetic field, their trajectory is [JIPMER 2002]
A)
Ellipse done
clear
B)
Circle done
clear
C)
Parabola done
clear
D)
None of these done
clear
View Solution play_arrow
question_answer 91)
At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit (i) Electrons (ii) Protons (iii) \[H{{e}^{2+}}\] (iv) Neutrons The emission at the instant can be [AIEEE 2002]
A)
i, ii, iii done
clear
B)
i, ii, iii, iv done
clear
C)
iv done
clear
D)
ii, iii done
clear
View Solution play_arrow
question_answer 92)
Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field [Orissa JEE 2002]
A)
Li+ done
clear
B)
Electron done
clear
C)
Proton done
clear
D)
\[H{{e}^{+}}\] done
clear
View Solution play_arrow
question_answer 93)
Mixed \[H{{e}^{+}}\] and \[{{O}^{2+}}\]ions (mass of \[H{{e}^{+}}=4\,\,amu\] and that of \[{{O}^{2+}}=16\,\,amu)\] beam passes a region of constant perpendicular magnetic field. If kinetic energy of all the ions is same then [Orissa JEE 2002]
A)
\[H{{e}^{+}}\] ions will be deflected more than those of \[{{O}^{2+}}\] done
clear
B)
\[H{{e}^{+}}\]ions will be deflected less than those of \[{{O}^{2+}}\] done
clear
C)
All the ions will be deflected equally done
clear
D)
No ions will be deflected done
clear
View Solution play_arrow
question_answer 94)
An electron (mass = 9´ 10?31kg. Charge = 1.6 ´ 10?19C) whose kinetic energy is 7.2 ´ 10?18 joule is moving in a circular orbit in a magnetic field of 9 ´ 10?5 weber/m2. The radius of the orbit is [MP PMT 2002]
A)
1.25 cm done
clear
B)
2.5 cm done
clear
C)
12.5 cm done
clear
D)
25.0 cm done
clear
View Solution play_arrow
question_answer 95)
An electron enters a region where electrostatic field is 20N/C and magnetic field is 5T. If electron passes undeflected through the region, then velocity of electron will be [DPMT 2002]
A)
\[0.25m{{s}^{-1}}\] done
clear
B)
\[2m{{s}^{-1}}\] done
clear
C)
\[4m{{s}^{-1}}\] done
clear
D)
\[8m{{s}^{-1}}\] done
clear
View Solution play_arrow
question_answer 96)
A charged particle is released from rest in a region of steady uniform electric and magnetic fields which are parallel to each other the particle will move in a [IIT-JEE 1999; DPMT 2000; UPSEAT 2003]
A)
Straight line done
clear
B)
Circle done
clear
C)
Helix done
clear
D)
Cycloid done
clear
View Solution play_arrow
question_answer 97)
A particle of mass M and charge Q moving with velocity \[\overset{\to }{\mathop{v}}\,\]describes a circular path of radius R when subjected to a uniform transverse magnetic field of induction B. The work done by the field when the particle completes one full circle is [AIEEE 2003]
A)
\[B\,Qv\,2\pi \,R\] done
clear
B)
\[\left( \frac{M{{v}^{2}}}{R} \right)\,2\pi R\] done
clear
C)
Zero done
clear
D)
\[BQ2\pi R\] done
clear
View Solution play_arrow
question_answer 98)
A particle of charge \[-16\times {{10}^{-18}}\]coulomb moving with velocity \[10\,\,m{{s}^{-1}}\] along the x-axis enters a region where a magnetic field of induction B is along the y-axis, and an electric field of magnitude \[{{10}^{4}}\,\,V/m\]is along the negative z-axis. If the charged particle continues moving along the x-axis, the magnitude of B is [AIEEE 2003]
A)
\[{{10}^{-3}}Wb/{{m}^{2}}\] done
clear
B)
\[{{10}^{3}}Wb/{{m}^{2}}\] done
clear
C)
\[{{10}^{5}}Wb/{{m}^{2}}\] done
clear
D)
\[{{10}^{16}}Wb/{{m}^{2}}\] done
clear
View Solution play_arrow
question_answer 99)
Two ions having masses in the ratio 1 : 1 and charges 1 : 2 are projected into uniform magnetic field perpendicular to the field with speeds in the ratio 2 : 3. The ratio of the radii of circular paths along which the two particles move is [EAMCET 2003]
A)
4 : 3 done
clear
B)
2 : 3 done
clear
C)
3 : 1 done
clear
D)
1 : 4 done
clear
View Solution play_arrow
question_answer 100)
An electron is travelling along the x-direction. It encounters a magnetic field in the y-direction. Its subsequent motion will be [AIIMS 2003]
A)
Straight line along the x-direction done
clear
B)
A circle in the xz-plane done
clear
C)
A circle in the yz-plane done
clear
D)
A circle in the xy-plane done
clear
View Solution play_arrow
question_answer 101)
An electron and a proton have equal kinetic energies. They enter in a magnetic field perpendicularly, Then [UPSEAT 2003]
A)
Both will follow a circular path with same radius done
clear
B)
Both will follow a helical path done
clear
C)
Both will follow a parabolic path done
clear
D)
All the statements are false done
clear
View Solution play_arrow
question_answer 102)
Electrons move at right angles to a magnetic field of \[1.5\times {{10}^{-2}}\]Tesla with a speed of \[6\times {{10}^{7}}m/s.\]If the specific charge of the electron is \[1.7\times {{10}^{11}}\]C/kg. The radius of the circular path will be [BHU 2003]
A)
2.9 cm done
clear
B)
3.9 cm done
clear
C)
2.35 cm done
clear
D)
3 cm done
clear
View Solution play_arrow
question_answer 103)
The cyclotron frequency of an electron grating in a magnetic field of 1 T is approximately [AIIMS 2004]
A)
28 MHz done
clear
B)
280 MHz done
clear
C)
2.8 GHz done
clear
D)
28 GHz done
clear
View Solution play_arrow
question_answer 104)
In the given figure, the electron enters into the magnetic field. It deflects in ...... direction [Orissa PMT 2004]
A)
+ ve X direction done
clear
B)
? ve X direction done
clear
C)
+ ve Y direction done
clear
D)
? ve Y direction done
clear
View Solution play_arrow
question_answer 105)
A proton of energy 8 eV is moving in a circular path in a uniform magnetic field. The energy of an alpha particle moving in the same magnetic field and along the same path will be [J & K CET 2004]
A)
4 eV done
clear
B)
2 eV done
clear
C)
8 eV done
clear
D)
6 eV done
clear
View Solution play_arrow
question_answer 106)
An electron, a proton, a deuteron and an alpha particle, each having the same speed are in a region of constant magnetic field perpendicular to the direction of the velocities of the particles. The radius of the circular orbits of these particles are respectively Re, Rp, Rd and Ra. It follows that [UPSEAT 2004]
A)
\[{{R}_{e}}={{R}_{p}}\] done
clear
B)
\[{{R}_{p}}={{R}_{d}}\] done
clear
C)
\[{{R}_{d}}={{R}_{\alpha }}\] done
clear
D)
\[{{R}_{p}}={{R}_{\alpha }}\] done
clear
View Solution play_arrow
question_answer 107)
An electron moving with a uniform velocity along the positive x-direction enters a magnetic field directed along the positive y-direction. The force on the electron is directed along [UPSEAT 2004]
A)
Positive y-direction done
clear
B)
Negative y-direction done
clear
C)
Positive z-direction done
clear
D)
Negative z-direction done
clear
View Solution play_arrow
question_answer 108)
An electron is projected along the axis of a circular conductor carrying some current. Electron will experience force [DCE 2002]
A)
Along the axis done
clear
B)
Perpendicular to the axis done
clear
C)
At an angle of 4o with axis done
clear
D)
No force experienced done
clear
View Solution play_arrow
question_answer 109)
A very high magnetic field is applied to a stationary charge. Then the charge experiences [DCE 2004]
A)
A force in the direction of magnetic field done
clear
B)
A force perpendicular to the magnetic field done
clear
C)
A force in an arbitrary direction done
clear
D)
No force done
clear
View Solution play_arrow
question_answer 110)
A electron (q = 1.6 ´ 10?19 C) is moving at right angle to the uniform magnetic field 3.534 ´ 10?5 T. The time taken by the electron to complete a circular orbit is [MH CET 2004]
A)
2 ms done
clear
B)
4 ms done
clear
C)
3 ms done
clear
D)
1 ms done
clear
View Solution play_arrow
question_answer 111)
In case Hall effect for a strip having charge Q and area of cross-section A, the Lorentz force is [DCE 2004]
A)
Directly proportional to Q done
clear
B)
Inversely proportional to Q done
clear
C)
Inversely proportional to A done
clear
D)
Directly proportional to A done
clear
View Solution play_arrow
question_answer 112)
A charged particle of mass m and charge q travels on a circular path of radius r that is perpendicular to a magnetic field B. The time taken by the particle to complete one revolution is [AIEEE 2005]
A)
\[\frac{2\pi qB}{m}\] done
clear
B)
\[\frac{2\pi \,m}{q\,B}\] done
clear
C)
\[\frac{2\pi \,m\,q}{B}\] done
clear
D)
\[\frac{2\pi \,{{q}^{2}}B}{m}\] done
clear
View Solution play_arrow
question_answer 113)
A very long straight wire carries a current \[I\]. At the instant when a charge \[+Q\] at point \[P\] has velocity \[\overrightarrow{V}\], as shown, the force on the charge is [CBSE PMT 2005]
A)
Opposite to OX done
clear
B)
Along OX done
clear
C)
Opposite to OY done
clear
D)
Along OY done
clear
View Solution play_arrow
question_answer 114)
The electron in the beam of a television tube move horizontally from south to north. The vertical component of the earth's magnetic field points down. The electron is deflected towards [KCET 2005]
A)
West done
clear
B)
No deflection done
clear
C)
East done
clear
D)
North to south done
clear
View Solution play_arrow
question_answer 115)
An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional to [CBSE PMT 2005]
A)
\[\frac{B}{v}\] done
clear
B)
\[\frac{v}{R}\] done
clear
C)
\[\sqrt{\frac{v}{B}}\] done
clear
D)
\[\sqrt{\frac{B}{v}}\] done
clear
View Solution play_arrow
question_answer 116)
An electric field of 1500 V / m and a magnetic field of 0.40 weber / meter2 act on a moving electron. The minimum uniform speed along a straight line the electron could have is [KCET 2005]
A)
1.6 ´ 1015 m / s done
clear
B)
6 ´ 10-16 m / s done
clear
C)
3.75 ´ 103 m / s done
clear
D)
3.75 ´ 102 m / s done
clear
View Solution play_arrow
question_answer 117)
An electron (mass = \[9.1\times {{10}^{-31}}\] kg; charge = \[1.6\times {{10}^{-19}}\]C) experiences no deflection if subjected to an electric field of \[3.2\times {{10}^{5}}\]V/m, and a magnetic fields of \[2.0\times {{10}^{-3}}\] Wb/m2. Both the fields are normal to the path of electron and to each other. If the electric field is removed, then the electron will revolve in an orbit of radius [BCECE 2005]
A)
45 m done
clear
B)
4.5 m done
clear
C)
0.45 m done
clear
D)
0.045 m done
clear
View Solution play_arrow
question_answer 118)
An electron, moving in a uniform magnetic field of induction of intensity \[\vec{B},\] has its radius directly proportional to [DPMT 2005]
A)
Its charge done
clear
B)
Magnetic field done
clear
C)
Speed done
clear
D)
None of these done
clear
View Solution play_arrow