Grade 7 : Science (Curiosity) - 3. Electricity (Set 4)

Question 1

Consider a simple circuit setup with a power source, a switch, and a light bulb. The wires connect all these components.

What is the primary role of the switch in this circuit?

Accepted Answer

C) To open or close the circuit, controlling the flow of current.

Answer

A) To increase the brightness of the bulb.

Answer

B) To convert electrical energy into light energy.

Answer

D) To store electrical energy for later use.

Question 2

A student is trying to identify materials that allow electricity to pass through them easily. They have a collection of items: a plastic ruler, a copper wire, a rubber band, and a glass rod.

Which of these items would be classified as a good conductor of electricity?

Accepted Answer

B) Copper wire

Answer

A) Plastic ruler

Answer

C) Rubber band

Answer

D) Glass rod

Question 3

Imagine three identical light bulbs connected in a series circuit to a battery.

If one of the light bulbs in this series circuit burns out, what will happen to the other two bulbs?

Accepted Answer

A) All the bulbs will go out.

Answer

B) The other two bulbs will shine brighter.

Answer

C) The other two bulbs will continue to glow normally.

Answer

D) Only the bulb directly next to the burnt-out bulb will go out.

Question 4

Consider a circuit where three identical light bulbs are connected in parallel to a power source.

If one of these light bulbs suddenly stops working, how will it affect the other two bulbs in the parallel circuit?

Accepted Answer

D) The other two bulbs will continue to glow normally.

Answer

A) All three bulbs will go out.

Answer

B) The remaining two bulbs will shine brighter.

Answer

C) The remaining two bulbs will glow dimly.

Question 5

An inventor is designing a small portable device that needs a continuous supply of electricity for several hours. They are considering different sources of electrical energy.

Which of the following is a common source of electrical energy for portable electronic devices?

Accepted Answer

B) Battery

Answer

A) Wind turbine

Answer

C) Hydroelectric dam

Answer

D) Solar panel (without storage)

Question 6

After rubbing a plastic comb through her hair, Maya notices that the comb can pick up small pieces of paper.

This phenomenon is an example of what type of electricity?

Accepted Answer

A) Static electricity

Answer

B) Current electricity

Answer

C) Alternating current

Answer

D) Direct current

Question 7

David is helping his father fix a broken electrical appliance. His father reminds him to always be careful and take precautions.

Which of the following is a crucial safety rule when working with electrical appliances or outlets?

Accepted Answer

C) Never touch electrical appliances with wet hands.

Answer

A) Always touch electrical wires with wet hands to check for current.

Answer

B) Use damaged electrical cords if new ones are not available.

Answer

D) Insert metal objects into electrical outlets to test them.

Question 8

Imagine two different circuits. Circuit A has a small 1.5V battery, and Circuit B has a larger 9V battery, each connected to an identical light bulb.

What difference would you observe in the brightness of the light bulbs, and why?

Accepted Answer

D) The bulb in Circuit B would be brighter because higher voltage provides more electrical push.

Answer

A) Both bulbs would be equally bright because they are identical.

Answer

B) The bulb in Circuit A would be brighter because it has less voltage.

Answer

C) The bulb in Circuit B would be dimmer because higher voltage makes the bulb work less efficiently.

Question 9

A simple circuit consists of a battery, a switch, and a small motor. The switch is currently in the 'OFF' position.

What type of circuit is this when the switch is 'OFF'?

Accepted Answer

B) Open circuit

Answer

A) Closed circuit

Answer

C) Short circuit

Answer

D) Parallel circuit

Question 10

A student wraps a copper wire around an iron nail and connects the ends of the wire to a battery. They observe that the nail temporarily becomes a magnet.

This setup demonstrates the principle of:

Accepted Answer

A) Electromagnetism

Answer

B) Electrostatics

Answer

C) Thermoelectricity

Answer

D) Photovoltaic effect

Question 11

When you turn on an electric fan, it starts to spin and produce moving air.

What energy transformation primarily occurs in an electric fan?

Accepted Answer

D) Electrical energy to mechanical energy

Answer

A) Chemical energy to electrical energy

Answer

B) Light energy to mechanical energy

Answer

C) Thermal energy to electrical energy

Question 12

Governments are increasingly promoting the use of energy sources that do not deplete naturally and have a lower environmental impact for electricity generation.

Which of the following is considered a renewable source for generating electricity?

Accepted Answer

A) Solar power

Answer

B) Coal

Answer

C) Natural gas

Answer

D) Nuclear fission (from uranium)

Question 13

  ───[ S ]───
  │         │
  [B1]  [B2]
  │         │
  ───[ V ]───

This diagram shows two light bulbs, B1 and B2, a switch S, and a voltage source V.

Based on the diagram, how are the light bulbs B1 and B2 connected?

Accepted Answer

C) In parallel

Answer

A) In series

Answer

B) In a short circuit

Answer

D) They are not connected in a functional circuit.

Question 14

Some electrical devices, like toasters or electric heaters, convert a significant amount of electrical energy into heat. This conversion is often due to a property of the material resisting the flow of current.

What property of a material describes its opposition to the flow of electric current?

Accepted Answer

D) Resistance

Answer

A) Conductivity

Answer

B) Voltage

Answer

C) Current

Question 15

To protect homes and appliances from damage caused by excessive electrical current, special safety devices are installed in the electrical system.

Which of the following devices is designed to automatically break an electrical circuit if the current becomes too high, preventing overheating and potential fires?

Accepted Answer

B) A circuit breaker

Answer

A) A light switch

Answer

C) A transformer

Answer

D) A resistor