#### Electricity Model Question Paper

7th Standard

Reg.No. :
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Science

Time : 01:00:00 Hrs
Total Marks : 50
4 x 1 = 4
1. In the circuit diagram below, 10 units of electric charge move past point x every second What is the current in the circuit ------------------------

(a)

10 A

(b)

1 A

(c)

10 V

(d)

1 V

2. In the circuit shown, which switches (L, M or N) must be closed to light up the bulb

(a)

switch L only

(b)

switch M only

(c)

Switch M and N only

(d)

either switch L or switches M and N

3. Small amounts of electrical current are measured in milliampere (mA). How many milliampere are there in 0.25 A ?

(a)

2.5 mA

(b)

25 mA

(c)

250 mA

(d)

2500 mA

4. In which of the following circuits are the bulb connected in series?

(a)

(b)

(c)

(d)

5. 3 x 1 = 3
6. One unit of coulomb is charge of approximately ------------------ protons or electrons.

()

6.242 x 1018

7. ------------------ is used to measure the electric current.

()

Ammeter

8. S.I. unit of Electrical conductivity of a conductor is --------------------

()

Siemens/meter (S/m)

9. 4 x 1 = 4
10. Electron flow is in the same direction to conventional current flow.

(a) True
(b) False
11. The fuse wire does not melts whenever there is overload in the wiring.

(a) True
(b) False
12. In a parallel circuit, the electric components are divided into branches.

(a) True
(b) False
13. The representation of the electric current is A.

(a) True
(b) False
14. 4 x 1 = 4
15. Cell

16. (1)

A complete path for the flow of an electric current

17. Switch

18. (2)

Safety device used in electric circuit

19. Circuit

20. (3)

Used to open or close a circuit

21. Fuse

22. (4)

A device which converts chemical energy into electrical energy.

3 x 2 = 6
23. Name the device used to generate electricity.

24. Define fuse.

25. Name some devices that run using heat effect of electric current

26. 3 x 3 = 9
27. Define an electric current.

28. Differentiate parallel and serial circuits.

29. Define electrical conductivity.

30. 4 x 5 = 20
31. Explain the construction and working of an Telephone.

32. Explain the heating effect of electric current.

33. Explain the construction and working of a dry cell.

34. A student made a circuit by using an electric cell, a switch, a torch bulb (fitted in the bulb holder) and copper connecting wires. When he turned on the switch, the torch bulb did not glow at all. The student checked the circuit and found that all the wire connections were tight.
1)What could be the possible reason for the torch bulb not glowing even when the circuit appears to be complete?