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Electricity and Circuits (HBBVS)

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Which of the following is a portable and safe source of electricity?

  1. Dry cell

  2. Electric generators

  3. Power socket

  4. Portable electric generators

  5. -


Correct Option: A
Explanation:

This is the correct answer. Dry cell is safe and portable source of electricity with each cell of 1.5 V.

Filament of an electric bulb is a thin wire of

  1. aluminium

  2. tungsten

  3. nichrome

  4. copper

  5. -


Correct Option: B
Explanation:

This is the correct answer. When electric current is passed through tungsten wire, it gets heated and produces light.

If four cells are joined in series, how much electricity will they produce?

  1. 1.5 V

  2. 3 V

  3. 6 V

  4. 6.5 V

  5. -


Correct Option: C
Explanation:

This is the correct answer. If four cells are joined in series, they will produce 6 V. Each cell is 1.5 V, so 4 * 1.5 = 6 V.

Which of the following energy can electrical energy be converted into?

  1. Mechanical

  2. Sound

  3. Magnetical

  4. All of the above

  5. -


Correct Option: D
Explanation:

This is the correct answer. Electrical energy can be changed into mechanical (moving a machine part), sound (loudspeaker) and magnetic energy (electromagnet).

How much electricity is provided to homes from power stations?

  1. 410 V

  2. 220 V

  3. 330 V

  4. 540 V

  5. -


Correct Option: B
Explanation:

This is the correct answer. Power stations provide 220 V to homes.

Why should the two terminals of a battery never be joined by a wire?

  1. The cell damages the wire.

  2. The cell gets used up very fast.

  3. The cell will catch fire.

  4. The cell gets heated up.

  5. -


Correct Option: B
Explanation:

This is the correct answer. If the two terminals of the battery are connected by a wire, the chemicals stored in it will be used up fastly, and cell will damage quickly.

Which are the positive and negative terminals of an electric bulb?

  1. Metal tip and metal case, respectively

  2. Metal case and metal tip, respectively

  3. Metal tip and glass case, respectively

  4. Glass case and metal tip, respectively

  5. -


Correct Option: A
Explanation:

This is the correct answer. Metal tip is the positive terminal and metal case is the negative terminal.

An electric bulb converts electrical energy to which of the following energies?

(a) Heat (b) Sound (c) Light (d) Magnetic

  1. Both (b) and (d)

  2. Only (c)

  3. Both (a) and (c)

  4. Only (a)

  5. -


Correct Option: C
Explanation:

This is the correct answer. Electric energy is converted into both, heat and light energy, in an electric bulb.

Which of the following is a conductor of electricity?

  1. Carbon

  2. Oxygen

  3. Nitrogen

  4. Hydrogen

  5. -


Correct Option: A
Explanation:

This is the correct answer. Carbon is the only non-metal, which is a good conductor of electricity, e.g. lead of a pencil.

Which component controls the working of a torch?

  1. Bulb

  2. Metal Case

  3. Sliding switch

  4. Cells

  5. -


Correct Option: C
Explanation:

This is the correct answer. Sliding switch acts as a switch in circuit, which can open and close a circuit.

Which of the following statements is/are not true?

(a) Electricity flow in open circuit (b) Electricity flow in closed circuit (c) Electricity flow when the switch is open (d) Electricity flow when the switch is closed

  1. Both (a) and (c)

  2. Both (c) and (d)

  3. Both (b) and (d)

  4. Both (a) and (d)

  5. -


Correct Option: A
Explanation:

This is the correct answer. Correct options are (a) Electricity flows in a closed circuit and (c) Electricity flows when the switch is closed.

A torch bulb which normally works on 4.5 V, is connected to a domestic supply of 220 V. What will happen to the torch bulb?

  1. It will glow very brightly.

  2. It will glow very dimly.

  3. It will not glow.

  4. It will get fused.

  5. -


Correct Option: D
Explanation:

This is the correct answer. When a high voltage electricity is given across the bulb, its wire melts due to high voltage and the bulb fuses.

Which materials are the plug case and electric plug made up of?

  1. Both are insulators.

  2. Both are conductors.

  3. Conductor and insulator, respectively

  4. Insulator and conductor, respectively

  5. -


Correct Option: D
Explanation:

This is the correct answer. Plug case is an insulator, so it is safe to to touch it. Electric plug is a conductor, used for carrying current.

In which of the following cases an electrical circuit may be broken?

(a) Circuit is made up of cotton threads. (b) Circuit is made up of copper wires. (c) Current flows from positive to negative. (d) Current flows from negative to positive.

  1. Both (b) and (c)

  2. Both (a) and (d)

  3. Both (a) and (c)

  4. Both (b) and (d)

  5. -


Correct Option: B
Explanation:

This is the correct answer. Circuit is broken when it is made up of cotton threads, as cotton is a bad conductor of electricity. Current cannot flow from negative to positive, so the circuit is broken.

Which of the following, when included in a completed circuit, would not let a torch blow glow?

  1. Paper clip

  2. Aluminium sheet

  3. Mica sheet

  4. Pencil lead

  5. -


Correct Option: C
Explanation:

This is the correct answer. Mica sheet is an insulator, which does not conduct electricity, so the bulb does not glow.

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