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#### Electricity Important Questions

10th Standard EM

Reg.No. :
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Science

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. Which of the following is correct?

(a)

Rate of change of charge is electrical power

(b)

Rate of change of charge is current.

(c)

Rate of change of energy is current.

(d)

Rate of change of current is charge.

2. SI unit of resistance is

(a)

mho

(b)

joule

(c)

ohm

(d)

ohm meter

3. A series circuit consists of three resistors with values of 140, 250 and 220. The total resistance is

(a)

330

(b)

610

(c)

720

(d)

None of the above

4. When one of three series resistors is removed from a circuit and the circuit is reconnected the current

(a)

increase by half

(b)

increases

(c)

decreases by half

(d)

none of the above

5. Which of the following laboratory apparatus is used during the verification of Ohm's law?

(a)

Voltmeter

(b)

Ammeter

(c)

Rheostat

(d)

All the above

6. 5 x 1 = 5
7. Electricity deals with the flow of __________ through a conductor

()

charges

8. Current passes from__________ potential to the_______ potential.

()

higher, lower

9. SIunit of current is __________

()

ampere

10. One coulomb of charge has ________ electrons.

()

6.25 x 1018

11. The device used to measure electric current is __________

()

ammeter

12. 5 x 1 = 5
13. electrical power

14. (1)

$\frac{1}{\rho}$

15. electrical energy

16. (2)

watt

17. Potential difference

18. (3)

$\frac{Q}{t}$

19. Electric current

20. (4)

joule

21. Conductivity

22. (5)

$\frac{W}{Q}$

2 x 5 = 10
23. Three resistors of 1 Ω, 2 Ω and 4 Ω are connected in parallel in a circuit. If a 1 Ω resistor draws a current of 1 A, find the current through the other two resistors.

24. 100 W bulb draws 680 mA current. How much time will be required to pass 30 C of charge through the bulb?

25. 4 x 2 = 8
26. Why is tungsten metal used in bulbs, but not in fuse wires?

27. Name any two devices, which are working on the heating effect of the electric current.

28. Why copper were is used as connecting wires in the circuit?

29. An electrician puts a fuse of rating 5 A in that part of domestic electrical circuit in which an electrical heater of rating 1.5 kW, 220V is operating. What is likely to happen in this case and why? What change, if any needs to be made?

30. 4 x 3 = 12
31. Define electric potential and potential difference.

32. What is the role of the earth wire in domestic circuits?

33. Distinguish between the resistivity and conductivity of a conductor.

34. Kalaivani was watching at a metal pipe, one end of which is connected to a tank at the top of her building and the other end to the tap, which is near the ground level. She was admiring how the water flows from top to the bottom through the pipe. She went and asked her mother, who was an engineer.
(i) Also Kalaivani asked her mother that can she able to compare this with any other scientific concepts?
(ii) How would her mother have compared
the resistance in a water pipe as well as in a conductor.
(ill) Give the expression for resistors connected in series and parallel.

35. 1 x 5 = 5
36. How many electrons are passing per second in a circuit in which there is a current of 5 A?