# 10th Class Physics Magnetic Effects of Electric Current Question Bank

### done Magnetic Effects of Electric Current

• A) South

B) West

C) Upward

D) Downward

• A) AC is not continuous.

B) DC cannot be generated.

C) There is very little loss of energy in AC transmission.

D) There is very little gain of energy in AC transmission.

• A) a direct current.

B) an alternating current.

C) a varying current.

D) a magnetic current.

• A) a current carrying wire.

B) a compass needle.

C) a scale and a ruler.

D) a bar magnet.

• A) west - east.

B) south - west.

C) north - south.

D) east - west.

• A) a DC motor.

B) a DC motor and an AC generator.

C) a DC generator.

D) an AC generator.

• A) circular loop.

B) moving coil.

C) straight conductor.

D) magnetic loop.

• A) an electric force.

B) magnetic induction.

C) a motor effect.

D) None of the above

• A) the diameter of the coil.

B) the strength of a magnet.

C) the thickness of the wire with which the coil is made.

D) All of the above.

• A) It is parallel to the plane of the coil.

B) It is perpendicular to the plane of the coil.

C) It is above the plane of the coil.

D) It is below the plane of the coil.

• A) Supply voltage is not correct.

B) Polarity of the magnets is wrong.

C) Polarity of the carbon brushes ${{B}_{1}}$and${{B}_{2}}$, is not correct.

D) Nothing is wrong with it.

• A) Torque is produced

B) An e.m.f.is induced.

C) Torque is not produced.

D) Both (a) and (b)

• A) A battery

B) Carbon brushes

C) A commutator

D) A permanent magnet

• A) It will rotate in clockwise direction.

B) It will rotate in anti-clockwise direction.

C) It will move to the right side.

D) It will move to the left side.

• A) A solenoid

B) A straight wire

C) A coil

D) A bar magnet

• A)

 Force on P Force on Q upwards upwards

B)

 Force on P Force on Q downwards downwards

C)

 Force on P Force on Q upwards downwards

D)

 Force on P Force on Q downwards upwards

• A) The type of current

B) The direction of current

C) The magnitude of current

D) The frequency of current

• A)

B)

C)

D)

• A) To ensure good contact between the stationary components and the moving components

B) To allow the coil to rotate continuously

C) To ensure the unidirectional flow & current.

D) To prevent the wires from getting entangled.

• A) It will become zero.

B) It will decrease.

C) It will increase.

D) It will remain the same.

• A) To ensure good contact between the stationary components and the moving components.

B) To allow the coil to rotate continuously.

C) To ensure the current flowing through the coil is direct current.

D) To prevent the wires from getting entangled.

• A) P has more magnitude than Q.

B) Q has more magnitude than P.

C) P and Q have the same magnitude.

D) P and Q may have the same or more magnitude.

• A) parallel to the field.

B) perpendicular to the field.

C) at an angle of$\text{45}{}^\circ$to the field.

D) at an angle of$\text{6}0{}^\circ$to the field.

• A) An increase in the number of turns in the coil

B) An increase in the area of cross- section of the coil

C) An increase in the size of the core

D) The winding of a large number of coils on the soft iron core

• A) Whenever magnetic flux linked with a circuit changes, induced e.m.f is produced.

B) The induced e.m.f lasts as long as the change in the magnetic flux continues.

C) The magnitude of the induced e.m.f is directly proportional to the rate of change of the magnetic flux linked with the circuit.

D) All of the above

• A) Ampere's law

B) Ohm's law

C) Lenz's law

•  (i) An increase in the number of turns of the coil (ii) An increase in the input of D.C. voltage (iii) The inserting of a copper core in the coil

A) Only (i) and (ii)

B) Only (i) and (iii)

C) Only (ii) and (iii)

D) (i), (ii) and (iii)

• A) A core

B) A commutator

C) Magnets

D) All of the above

• A) momentum.

B) energy.

C) charge.

D) magnetism.

• A) On the direction of the current but not on the direction of the magnetic field

B) On the direction of the magnetic field but not on the direction of the current

C) On the direction of the current as well as the direction of the magnetic field

D) Neither on the direction of the current nor on the direction of the magnetic field

• A) Both the needles will not deflect.

B) Only needle P will deflect.

C) Both the needles will deflect in the same direction.

D) Both the needles will deflect in the opposite direction.

• A) Galvanometer

B) D.C. motor

C) A.C. motor

D) D.C. generator

• A) P

B) Q

C) R

D) S

•  Direction of magnetic field Direction of current (i) Maintain Reverse (ii) Reverse Maintain (iii) Reverse Reverse

A) Only (i)

B) Only (ii)

C) Only (iii)

D) Only (i) and (ii)

• A) an A.C. generator has commutator and a D.C. generator has slip rings.

B) an A.C. generator has slip rings and a D.C. generator has commutator.

C) A.C. generator rotates only in one direction.

D) the polarity of the current changes for every half rotation in a D.C. generator.

• A)

 Polarity at Y Direction of the current N-pole From the left

B)

 Polarity at Y Direction of the current N-pole From the right

C)

 Polarity at Y Direction of the current S-pole From the left

D)

 Polarity at Y Direction of the current S-pole From the right

• A)

B)

C)

D)

• A) To increase the rotational speed of the coil

B) To prevent the wire from getting entangled

C) To change the direction of current flowing to the load in every half a turn

D) To ensure good contact between the moving parts and the stationary parts

•  (i) Increasing the rotating speed of the coils (ii) Placing a soft iron core in the coil (iii) Replacing the permanent magnets with another pair of magnets having stronger magnetic field strength

A) Only (i) and (ii)

B) Only (ii) and (iii)

C) Only (i) and (iii)

D) (i), (ii) and (iii)

• A)

 Magnetic field Direction Circular Clockwise

B)

 Magnetic field Direction Elliptical Anticlockwise

C)

 Magnetic field Direction Circular Anticlockwise

D)

 Magnetic field Direction Elliptical Clockwise