Here in this post we provided NCERT Exemplar Problem Class 6 Science Electricity and Circuits Chapter 12 Full Explanation by group of Science Experts. We have provided here each questions answer with reason behind the answer.
Hope it help you!
Electricity and Circuits Class 6 Exemplar full Explanation:
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Multiple Choice Questions
1) Choose form the options a, b, c and d given in fig. 12.1 the figure which shows the correct direction of current.
Answer:- b)
Figure b is showing the correct direction of current .
2) Choose the incorrect statement.
a) A switch is the source of electric current in a circuit.
b) A switch help to complete or break the circuit.
c) A switch helps us to use electricity as per our requirement.
d) When the switch is open there is an air gap between it’s terminal.
Answer:- a) A switch is the source of electric current in a circuit.
Electric cell is a source of electric current in a circuit.
3) In an electric bulb , light is produced due to the glowing of
a) The glass case of the bulb.
b) The thin filament.
c) The thick wires supporting the filament.
d) Gases inside glass case of the bulb.
Answer:- b) the thin filament.
Filament is made up of a tungsten which glows on supplying an electric current and the light is produced.
4) In the following arrangement shown in fig. 12.2 the bulb will not glow if the ends A and B are connected with
a) A steel spoon
b) A metal clip
c) A plastic clip
d) A copper wire
Answer:- c) A plastic clip
Plastic is bad conductor of electricity thus is plastic cap will be there then bulb will not glow.
5) In the circuit shown in fig. 12.3 when the switch is moved to ‘ON’ position.
a) The blub A will glow first.
b) The bulb B will glow first.
c) The bulb C will glow first.
d) All bulbs will glow together.
Answer:- d) All bulbs will glow together.
All the bulbs are connected to the same in the circuit, and the two ends of the wires are connected to same batteries thus when circuit is closed all the light will glow at the same time.
6) Filament of a torch bulb is
a) A metal case.
b) Metal tip at the centre of the base.
c) Two thick wires.
d) A thin wire.
Answer:- d) A thin wire.
Filament is a thin wire made up of tungsten which glows and give light when connected to the electric circuits.
7) Paheli is running short of connecting wires. To complete an electric circuit, she may use a
a) Glass bangle.
b) Thick thread
c) Rubber pipe
d) Steel spoon .
Answer:- d) steel spoon.
Steel is a good conductor of electricity thus steel spoon can complete an electric circuit.
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Very Short Answer Questions
8) In which of the following circuits A, B, and C given in fig. 12.4 the cell will be used up very rapidly?
Answer:- In circuit A , cell is connected directly to the wires which will exhaust the energy very fast and thus the cell will used up rapidly in these position .
9) Fig. 12.5 shows a bulb with its different parts marked as 1, 2, 3, 4 and 5. Which of them label the terminals of the bulb?
Answer:- according to the figure, label 3 and 4 are the terminals of the bulb.
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Short Answer Questions
10) You are provided with a bulb, a cell, a switch and some connecting wires. Draw a diagram to show the connections between them to make the bulb glow.
Answer:-
diagram showing the connection between the wire, bulb , cell and switch.
11) Will the bulb glow in the circuit shown in fig. 12.6 ? Explain.
Answer:- The bulb in circuit can glow only when the switch is closed and the circuit is complete. But in the given diagram the switch is open and thus the circuit is incomplete. Therefore the bulb will not glow.
12) An electric bulb is connected to a cell through a switch as shown in fig. 12.7. when the switch is brought in ‘ON’ position. The bulb does not glow. What would be the possible reason/s for it? Mention any two of them.
Answer:- the possible reasons for the bulb does not glow will be as follows-
1) The cell is used.
2) The bulb may be fused.
3) Wires may be cut.
4) There will not be connection.
13) A torch requires 3 cells. Show the arrangement of the cells, with a diagram , inside the torch so that the bulb glows.
Answer:-
14) When the chemicals in the electric cell are used up, the electric cell stops producing electricity. The electric cell is then replaced with a new one. In case of rechargeable batteries ( such as the type used in mobile phones, camera and inverters) they are used again and again. How?
Answer:- Rechargeable batteries are made up of the purpose for the production of electricity when it is used up. These are recharged when the batteries are used up and it stops working. After recharge it again provide the current for working of the gadgets. Thus they are used again and again.
15) Paheli connected two bulbs to a cell as shown in fig. 12.8
She found that filament of bulb B is broken, will the bulb A glow in this circuit? Give reason.
Answer:- No. Bulb A will not glow in the given circuit. Because the circuit is incomplete. As the circuit is incomplete current will flow for the glowing of bulb.
16) Why do bulbs have two terminals?
Answer:- Current is always flows from negative to positive direction. Thus two terminals are necessary to connect the filament with the circuit. Then the current will pass through it.
17) Which of the following arrangement A, B, C and D given in fig. 12.9 should not be set up? Explain. Why?
A
B
C
D
Answer:-
Arrangement A should not be set up. Because if the cell and wires are connected like these then the cell will exhaust very fast.
18) A fused bulb does not glow. Why?
Answer:-
A fused bulb contains a broken filament and an incomplete circuit therefore a fused bulb does not glow.
19) Paheli wanted to glow a torch using a cell. She could not get connected wires, she got two strips of aluminium foil. Will she succeed? Explain, how?
Answer:- yes, As paheli don’t have an wire but she has aluminium foil which can act as an connecting wires. Aluminium is a good conductor of electricity thus the current can be passed from it and it glow the light of torch.
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Long Answer Questions
20) Boojho has a cell and a single piece of connecting wire. Without cutting the wire in two, will he be able to make the bulb glow? Explain with the help of a circuit diagram.
Answer:- yes, He can glow the light without cutting the wire in two pieces as doing the following arrangements of the bulb, battery and a wire.
21) Fig. 12.10 A and B , show a bulb connected to a cell in two different ways.
i) What will be the direction of the current through the bulb in both the cases. (Q to P or P to Q)
Answer:- As per the given information from the figure the current will flow like-
In fig. (1) → B to A
In fig. (2) → A to B
ii) will the bulb glow in both the cases?
Answer:- yes, the bulb will glow in both the cases. Both the ends of the batteries can work as an positive and negative terminals.
iii) Does the brightness of the glowing bulb depend on the Direction of current through it?
Answer:- No. The brightness does not depend on the direction of the current flowing through it. But it is dependent on the power of the batteries.
22) Think of six activities which use electric current. Also name the devices used to perform the activity.
Activity you
perform Device
Example: get light torch
___________ _________
___________ _________
___________ __________
___________ __________
___________ __________
Answer:-
Activity you perform Device
Get light→ Torch
Heat water → Geyser/ immersion rod
Make toast→ Toaster
Cook food→ Heater / microwave
Listen to music→ CD player / radio
23) A torch is not functioning, though contact points in the torch are in working condition. what can be the possible reasons for this? Mention any three.
Answer:-
Torch is not functioning although the contact points are in working condition.
Then the possible reasons are as follows-
1) The cells may be used up. There will not power in the cell.
2) The cells may not be placed correctly.
3) Switch may not be in working condition.
4) The bulb will not be in working condition.