Magnetic effect of current Worksheet-3

Magnetic effect of current Worksheet-3

 

  1. When a fuse is rated at 8 A, it means :

A. it will not work if current is less than 8 A

B. it has a resistance of 8 ohm

C. it will work only if current is 8 A

D. it will burn if current exceeds 8 A.

 

  1. According to International Convention of colour coding of wires used in household electrical circuits :

A. live is red, neutral is black and earth is green

B. live is red, neutral is green and earth is black

C. live is brown, neutral is blue and earth is black

D. live is brown, neutral is light blue and earth is green.

 

  1. For making a strong electromagnet, the material of the core should be :

A. soft iron                                     B. steel

C. brass                                           D. laminated steel strips.

 

  1. A soft iron bar is introduced inside a current-carrying solenoid. The magnetic field inside the solenoid :

A. will become zero                      B. will decrease

C. will increase                             D. will remain unaffected

 

  1. The most suitable material for making permanent magnets is :

A. iron                B. steel               C. copper           D. aluminium

 

  1. The magnetic field lines inside a current  carrying solenoid are :

A. along the axis and parallel to each other

B. perpendicular to the axis and equidistant from each other

C. circular and they do not intersect each other

D. circular at the ends but they are parallel to the axis inside the solenoid.

 

  1. The magnetic field lines inside a current carrying solenoid are :

A. parabolic      B. curved           C. straight         D. circular

 

  1. Potential difference between a live wire and the neutral wire is :

A. 150 V             B. 210 V             C. 200V             D. 220V

 

  1. A device for producing electric current is called:

A. galvanometer                           B. ammeter

C. generator                                   D. voltmeter.

 

  1. An electric motor converts :

A. mechanical energy into electrical energy

B. mechanical energy into heat energy

C. electrical energy into heat energy

D. electrical energy into mechanical energy.

 

  1. An electric generator converts

A. electrical energy into mechanical energy

B. mechanical energy into heat energy

C. electrical energy into chemical energy

D. mechanical energy into electrical energy.

 

  1. The ring system of wiring is better than the tree system because :

A. less power is consumed in the ring system

B. it can work even at low voltage supply

C. it is less expensive

D. all appliances can be joined in series.

 

  1. From a power-station, the power is transmitted at a very high voltage because :

A. it is generated only at high voltage

B. it is cheaper to produce electricity at high voltage

C. electricity at high voltage is less dangerous

D. there is less loss of energy in transmission at high voltage.

 

  1. Power is transmitted from a power-house on high voltage AC as:

A. the Tate of transmission is faster at high voltage

B. it is more economical due to the less power wasted

C. power cannot be generated at low voltages

D. a precaution against theft of transmission lines.

 

Answer Key:

  1. D
  2. D
  3. A
  4. C
  5. B
  6. A
  7. C
  8. D
  9. C
  10. D
  11. D
  12. C
  13. D
  14. B