List of Factors Affecting Induced Current, Induced E.M.F, etc.

Important Past Questions:

  • State two ways to increase the speed of rotation of a D.C Motor.


  • How is the e.m.f across primary and secondary coils of a transformer related with the number of turns of coil in them?


  • On which type of current do transformers work?


  • State two advantages of electromagnets over permanent magnets. 

(2006, 2018)

  • State two causes of energy loss in a transformer. 


  • Which coil of a step-up transformer is made thicker and why?


  • On reversing the direction of the current in a wire, the magnetic field produced by it gets ________.


  • i) Why does a current carrying, freely suspended solenoid rest along a particular direction?

ii) State the direction in which it rests.

(2007, 2015)

  • Give two similarities between an A.C generator and a D.C motor.

(2008, 2015)

  • Name a common device that uses electromagnets. 


  • i) What is an A.C generator or dynamo used for?

ii) Name the principle on which it works. 


  • Give two differences between a D.C motor and an A.C generator.

(2008, 2010)

  • A device is used to transform 12V A.C to 200V A.C.

i) What is the name of this device?

ii) Name the principle on which it works.


  • i) What is the name given to a cylindrical coil whose diameter is less in comparison to its length?

ii) If a piece of soft iron is placed inside the current carrying coil, what is the name given to the device?

iii) Give one use of the device named above.


  • Why does a magnetic/compass needle show a deflection when brought close to a current carrying conductor?

(2007, 2008)

  • A wire bent into a circle carries current in an anticlockwise direction. What polarity does this face of the coil exhibit?


  • State two factors on which the strength of induced current depend.


  • What energy conversion takes place during the working of a D.C motor?


  • What is the function of the split rings in a D.C motor?


  • State one advantage of A.C over D.C.


  • State two ways by which the magnetic field of a solenoid can be made stronger.


  • What material is used for making the armature of an electric bell? Give a reason for using this material.


  • How does the heat produced in a wire or a conductor depend upon the:

1) current passing through the conductor

2) resistance of the conductor



  • Draw a neat labelled diagram of an A.C generator. (2009, 2019)

  • Draw a simple labelled diagram of a D.C electric motor. (2013)

  • Draw a simple sketch of a step down transformer. Label the different parts in the diagram. (2008)

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