7th Class Science Electric Current and Its Effects Question Bank

done Electric Current and Its Effects Total Questions - 20

• question_answer1)
  When current is passed through a conductor,  the heat produced in it depends upon

  I. The material of the conductor

  II. The current flowing through the conductor

  III. The time for which the current flows.

  A)
  I and II only                       done clear
  B)
  I and III only                      done clear
  C)
  II and III only    done clear
  D)
                     All I, II and III                        done clear
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• question_answer2)
  Which of the following appliances does not use an electromagnet?                 
  A)
  Washing machine                 done clear
  B)
  Refrigerator      done clear
  C)
                    Electric heater   done clear
  D)
                   Electric bell                        done clear
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• question_answer3)
  When the strength of the current flowing through a coil is increased, which of the following statements is true for it?       
  A)
  Strength of the magnetic field decreases,                      done clear
  B)
  Strength of the magnetic field increases,                       done clear
  C)
  Amount of heat generated due to resistance decreases,             done clear
  D)
  Strength of the magnetic field remains constant,                           done clear
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• question_answer4)
  Which of the following does not work on I the heating effect of current?     
  A)
                        done clear
  B)
    done clear
  C)
              done clear
  D)
         done clear
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• question_answer5)
  The magnetic field around a current carrying coil
  A)
  Lasts for three hours done clear
  B)
  Lasts as long as current flows through it done clear
  C)
  Lasts till its half-life period done clear
  D)
  Is permanent. done clear
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• question_answer6)
  Which of the following is not a circuit element?
  A)
  Battery done clear
  B)
  Voltmeter done clear
  C)
  Potential difference done clear
  D)
  Resistor done clear
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• question_answer7)
  A fuse wire is made up of alloy
  A)
  Nichrome done clear
  B)
  Tin-lead done clear
  C)
  Manganin done clear
  D)
  Constantan. done clear
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• question_answer8)
  In which of the following circuits bulb will glow?
  A)
  done clear
  B)
  done clear
  C)
  done clear
  D)
  done clear
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• question_answer9)
  Marking on a bulb is 60 W, 220 V. What does it signify?
  A)
  The bulb is connected across the 220 volts, 60 joules of energy is consumed for every second. done clear
  B)
  The bulb is connected across 220 volts, 60 joules of energy is released. done clear
  C)
  60 unit of current will flow in the bulb. done clear
  D)
  220 unit of current will flow in the bulb. done clear
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• question_answer10)
  Match the two columns and select the correct option from codes given below.

  Column I	Column II
  (a) A bad conductor of electricity but good conductor of heat	(i)  CFL
  (b) A wire twisted Nichrome many times in the form of circles	(ii) Nichrome
  (c) Smart eco-friendly bulb	(iii) Mica
  (d) An alloy whose temperature can rise up to \[{{900}^{o}}C\]and used as heating Element	(iv) Coil

             
  A)
  (a)-(iv),  (b)-(iii),  (c)-(ii),  (d)-(i) done clear
  B)
  (a)-(i),   (b)-(ii),   (c)-(iii), (d)-(iv) done clear
  C)
  (a)-(iii),  (b)-(iv),  (c)-(i),   (d)-(ii) done clear
  D)
  (a)-(ii),   (b)-(iv),  (c)-(i),   (d)-(iii) done clear
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• question_answer11)
  Observe the given circuit diagrams (X and Y) and identify the correct statement.
  A)
  Circuit Y is a series circuit. done clear
  B)
  Bulb 2 in circuit X will glow, even when the bulb 1 is fused, and switch \[{{S}_{1}}\] is closed. done clear
  C)
  In circuit Y, bulb 3 will glow if only switch \[{{S}_{2}}\] is closed. done clear
  D)
  Both circuits X and Y are parallel circuits. done clear
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• question_answer12)
  Which of the following statements is incorrect for the given circuit?            
  A)
  The wire has no magnetic effect. done clear
  B)
  When compass is kept near to the circuit, it will not show any deflection. done clear
  C)
  The given circuit is incomplete because there is no source of electric energy. done clear
  D)
  Due to battery in this circuit, electric wire behaves as a magnet. done clear
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• question_answer13)
  In which circuit the bulbs will glow brightly?
  A)
  In circuit P only done clear
  B)
  In circuit Q only done clear
  C)
  In both circuits P and Q, the bulbs will glow with equal brightness done clear
  D)
  Neither P nor Q done clear
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• question_answer14)
  Which of the following diagrams represents a short circuit?
  A)
       done clear
  B)
      done clear
  C)
  done clear
  D)
         done clear
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• question_answer15)
  Copper wires are used as connecting wires because  
  A)
  Copper has very high melting point done clear
  B)
  Copper wires are very thick wires        done clear
  C)
  Copper wire offers a lower resistance done clear
  D)
  None of these   done clear
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• question_answer16)
  Three bulbs A, B and C are connected as shown in figure. The bulbs B and C are identical. If the bulb C is fused, then
  A)
  Brightness of both bulbs A and B will increase done clear
  B)
  Brightness of both bulbs A and B will decrease            done clear
  C)
  Brightness of the bulb A decreases       and that of bulb B increases    done clear
  D)
  None of the bulbs will glow.     done clear
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• question_answer17)
  Consider the following statements and select the correct option which correctly identifies true (T) and false (F).           

  (i) Iron loses its magnetism easily,

  (ii) Steel is a hard magnetic material.

  (iii) Iron is used to make permanent magnet,

  (iv) Steel is used to make electromagnet,

   
  A)

  (i)	(ii)	(iii)	(iv)
  F	F	T	T

    done clear
  B)

  (i)	(ii)	(iii)	(iv)
  T	T	F	F

    done clear
  C)

  (i)	(ii)	(iii)	(iv)
  T	F	T	F

    done clear
  D)

  (i)	(ii)	(iii)	(iv)
  F	T	F	T

    done clear
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• question_answer18)
  Which of the following circuit diagram represents the given torch?
  A)
       done clear
  B)
    done clear
  C)
         done clear
  D)
                         done clear
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• question_answer19)
  In the given figures, there are four electromagnets. Which electromagnet is stronger?
  A)
             done clear
  B)
  done clear
  C)
         done clear
  D)
           done clear
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• question_answer20)
  Read the given statements and select the correct option.                          

  Statement 1: In a circuit, surface of the bulb becomes warmer than the connecting wires when the same current flows through them.

  Statement 2: A thin and long wire has higher resistance than a thick and short wire.

  A)
  Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1. done clear
  B)
  Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1. done clear
  C)
  Statement 1 is true and statement 2 is false. done clear
  D)
  Statement 2 is true and statement 1 is false. done clear
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