CBSE - Electricity

1 Electricity A wire of resistance R is stretched to twice of its original length. Its new resistance will be :

(1) 4R
(2) R / 4
(3) 2R
(4) R / 2

2 Electricity A certain household has consumed 200 units of energy during a month. Its value in joules will be -

(1) 3.6 × 10¹⁰
(2) 7.2 × 10¹⁰
(3) 3.6 × 10⁸
(4) 7.2 × 10⁸

3 Electricity It is written 100 watt-250 volt on any bulb. Its resistance will be

(1) 25000 ohm
(2) 625 ohm
(3) 25 ohm
(4) 2.5 ohm

4 Electricity The value of equivalent resistance between the points A and B in the given circuit, will be –


(1) 6R
(2) 4R/11
(3) 11R/4
(4) R/6

5 Electricity 

In an experiment on finding equivalent resistance of two resistors in series, four students draw up circuits - which oneis correct ?

6 Electricity If current through a resistance is increased by 100% simultaneously reducing resistance value to 25%, the new power
dissipated will be
(1) No change
(2) Increased by 100%
(3) Decreased by 400%
(4) Increased by 400%

7 Electricity 

An ammeter can read current upto 5 A and it has twenty divisions between the mark 0 and mark 2A on its scale

The least count of the ammeter is

(1) 0.02 A
(2) 0.01 A
(3) 0.2 A
(4) 0.1 A

8 Electricity When 1 J of work is done to move a charge of 1 C from one point to another point then the potential difference between two points in a given circuit will be-

(1) 1 V
(2) 4V
(3) 8 V
(4) zero

9 Electricity The device used for measuring electric current is

(1) generator
(2) galvanometer
(3) ammeter
(4) motor

10 Electricity In house electrical circuit s the fuse wire for safety should be of
(1) High resistance - high melting point
(2) Low resistance - high melting point
(3) Low resistance - low melting point
(4) High resistance - low melting point