### Current Electricity

1. 1 angstrom is equal to

1. 10-8 mm
2. 10"6 cm
3. 10"10 m
4. 10∼14 m

10"10 m

2. A 3 Q resistor having 2 A current will dissipate the power of

1. 2 watts
2. 4 watts
3. 6 watts
4. 8 watts

6 watts

3. A 40 W bulb is connected in series with a room heater. If now 40 W bulb is replaced by 100 W bulb, the heater output will

1. decrease
2. increase
3. remain same
4. heater will burn out

increase

4. A closed switch has a resistance of

1. zero
4. infinity

zero

5. A current of 16 amperes divides between two branches in parallel of resistances 8 ohms and 12 ohms respectively. The current in each branch is

1. 6.4 A, 6.9 A
2. 6.4 A, 9.6 A
3. 4.6 A, 6.9 A
4. 4.6 A, 9.6 A

6.4 A, 9.6 A

6. A field of force can exist only between

1. two molecules
2. two ions
3. two atoms
4. two metal particles

two ions

7. A glass rod when rubbed with silk cloth is charged because

1. it takes in proton
2. its atoms are removed
3. it gives away electrons
4. it gives away positive charge

it gives away electrons

8. A light bulb draws 300 mA when the voltage across it is 240 V. The resistance of the light bulb is

1. 400 Q
2. 600 Q
3. 800 Q
4. 1000 Q

800 Q

9. A nichrome wire used as a heater coil has the resistance of 2 £2/m. For a heater of 1 kW at 200 V, the length of wire required will be

1. 80 m
2. 60 m
3. 40 m
4. 20 m