Electricity

Samacheer Book Back Questions And Answers For Science Standard 8 “Electricity“

I. Choose the best answer:
1. When an ebonite rod is rubbed with fur, the charge acquired by the fur is
a. negative
b. positive
c. partly positive and partly negative
d. None of these

2. The electrification of two different bodies on rubbing is because of the transfer of
a. neutrons
b. protons
c. electrons 
d. protons and neutrons

3. Which of the following a simple circuit must have?
a. Energy source, Battery, Load
b. Energy source, Wire, Load
c. Energy source, Wire, Switch
d. Battery, Wire, Switch

4. An electroscope has been charged by induction with the help of charged glass rod. The charge on the electroscope is _____.
a. negative
b. positive
c. both positive and negative
d. None of the above

5. Fuse is
a. a switch
b. a wire with low resistance
c. a wire with high resistance
d. a protective device for breaking an electric circuit

II. Fill in the blanks:
1. _____ takes place by rubbing objects together.
2. The body which has lost electrons becomes _____.
3. _____ is a device that protects building from lightning strike.
4. _____ has a thin metallic filament that melts and breaks the connection when the circuit is overheated.
5. Three bulbs are connected end to end from the battery. This connection is called _____.

Answers:
1. Transfer of electron
2. Positive
3. Lightning arrestor
4. Electric fuse
5. Series circuit

III. State true or false. If false, correct the statement:
1. The charge acquired by an ebonite rod rubbed with a piece of flannel is negative.
2. A charged body induces an opposite charge on an uncharged body when they are brought near.
3. Electroscope is a device used to charge a body by induction.
4. Water can conduct electricity.
5. In parallel circuit, current remains the same in all components.

Answers:
1. True
2. True
3. True
4. True
5. False (In parallel circuit, voltage remains the same in all components)

IV. Match the following:
1. Two similar charges                                    A. acquires a positive charge
2. Two dissimilar charges                               B. prevents a circuit from overheating
3. When glass rod is rubbed with silk            C. repel each other
4. When ebonite rod is rubbed with fur        D. attract each other
5. Fuse                                                            E. acquires a negative charge

Answers:
1. C
2. D
3. A
4. E
5. B

VI. Consider the statements given below and choose the correct option:
1. Assertion: People struck by lightning receive a severe electrical shock.
Reason: Lightning carries very high voltage.
a. Both assertion and reason are true and reason is the correct explanation of assertion.
b. Both assertion and reason are true and reason is not the correct explanation of assertion.
c. Assertion is true but reason is false.
d. Assertion is false but reason is true.

2. Assertion: It is safer to stand under a tall tree during lightning
Reason: It will make you the target for lightning.
a. Both assertion and reason are true and reason is the correct explanation of assertion.
b. Both assertion and reason are true and reason is not the correct explanation of assertion.
c. Assertion is true but reason is false.
d. Assertion is false but reason is true.

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