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VI - SCIENCE - ELECTRICITY - EVALUATION - QUESTION AND ANSWERS
ELECTRICITY
EVALUATION
I. Choose the appropriate answer
1. The device which converts chemical energy into electrical energy is
a. fan
b. solar cell
c. cell
d. Television
Ans: c. cell
2. Electricity is produced in
a. transformer
b. power station
c. electric wire
d. Television
Ans: b. power station
3. Choose the symbol for battery
Ans:
4. In which among the following circuits does the bulb glow?
Ans:
5. ______ is a good conductor
a. silver
b. wood
c. rubber
d. Plastic
Ans: a. silver
II. Fill in the blanks
1. ____________ are the materials which allow electric current to pass through
Them.
Ans: Conductors
2. Flow of electricity through a closed circuit is ____________.
Ans: current
3. ____________ is the device used to close or open an electric circuit.
Ans: Switch
4. The long perpendicular line in the electrical symbol represents its ____________ terminal.
Ans: positive
5. The combination of two or more cells is called a ____________.
Ans: battery
III. True or False. If False, give the correct statement
1. In a parallel circuit, the electricity has more than one path.
Ans: True
2. To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell.
Ans: False. To make a battery of two cells, the positive terminal of one cell is connected to the negative terminal of the other cell.
3. The switch is used to close or open an electric circuit.
Ans: True
4. Pure water is a good conductor of electricity.
Ans: False
5. Secondary cells can be used only once.
Ans: False. Primary cell can be used only once
IV . Match the following
Ans:
V. Arrange in sequence
Ans:
VI. Give very short answer
1. In the given circuit diagram, which of the given switch(s) should be closed. So that only the bulb A glows.
Ans: K1 and K2 switches should be closed
2. Assertion (A) : It is very easy for our body to receive electric shock.
Reason (R) : Human body is a good conductor of electricity.
a. Both A and R are correct and R is the correct explanation for A.
b. A is correct, but R is not the correct explanation for A.
c. A is wrong but R is correct.
d. Both A and R are correct and R is not the correct explanation for A.
Ans: a. Both A and R are correct and R is the correct explanation for A.
3. Can you produce electricity from lemon?
Ans: Yes, I can generate electricity by using lemon. In addition,copper and aluminium pieces are needed to be used as electrodes, here lemon juice will function as an electrolyte.
4. Identify the conductor from the following figures
Ans: Iron chain
5. What type of circuit is there in a torch light?
Ans: Simple circuit.
6. Circle the odd one out. Give reason for your choice.
Switch, Bulb, Battery, Generator.
Ans: Generator. Generator is used to generate electricity while the others are components used in electric circuits.
VII. Give short answer
1. Draw the circuit diagram for series connection.
2. Can the cell used in the clock gives us an electric shock? Justify your answer.
No. The cell used in the clock does not give shock to the human body, it has very low voltage, which will not affect the human body.
3. Silver is a good conductor but it is not preferred for making electric wires.
Why?
Though silver is a good conductor, we are not preferred for making electric wires, because silver is very expensive.
VIII. Answer in detail
1. What is the source of electricity? Explain the various power stations in
India?
Any device from which electricity is produced is called the source of electricity.
We get electricity from different sources.
1. Thermal Power stations:
In thermal power stations, the thermal energy generated by burning coal, diesel or gas is used to produce steam. The steam thus produced is used to rotate the turbine. While the turbine rotates, the coil of wire kept between the electromagnet rotates. Due to electromagnetic induction electricity is produced. Here heat energy is converted into electrical energy.
2. Hydel power stations:
In hydel power stations, the turbine is made to rotate by the flow of water from dams to produce electricity. Here kinetic energy is converted into electrical energy. Hydel stations have long economic lives and low operating cost.
3. Atomic power stations:
In atomic power stations, nuclear energy is used to boil water. The steam thus produced is used to rotate the turbine. As a result, electricity is produced. Atomic power stations are also called nuclear power stations. Here nuclear energy is converted into mechanical energy and then electrical energy.
4. Wind mills:
In wind mills, wind energy is used to rotate the turbine to produce electricity. Here kinetic energy is converted into electrical energy.
2. Tabulate the different components of an electric circuit and their respective
Symbols.
3. Write short notes on conductors and insulators.
Conductors :
The rate of flow of electric charges in a circuit is called electric current. The materials which allow electric charges to pass through them are called conductors. Examples: Copper, iron, aluminum, impure water, earth etc.,
Insulators (Non-Conductors):
The materials which do not allow electric charges to pass through them are called insulators or nonconductors.
Examples: plastic, glass, wood, rubber, china clay, ebonite etc.,
IX. Question based on Higher Order Thinking Skills
1. Rahul wants to make an electric circuit. He has a bulb, two wires, a safety
pin and a piece of copper. He does not have any electric cell or battery.
Suddenly he got some idea. He uses a lemon instead of a battery and makes
a circuit. Will the bulb glow?
Yes. The bulb will glow.
Safety pin and piece of copper will act as electrodes. Lemon juice functions as electrolyte.
Safety pin and copper piece should be inserted into the lemon, and the electrodes and bulbs are to be connected using wires, then the bulb will glow. (Keep in mind that only low voltage bulb will glow)
