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Answer the following. (Class 10 Science 2023, Q32A)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 3 marks · Short answer

CBSE Class 10 Science 2023: question 32(A)

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, section C, question 32(A), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q32(A) · 3 marks · Short answerMagnetic Effects of Electric Current

Answer the following.

  1. (i)

    Why is an alternating current (A.C.) considered to be advantageous over direct current (D.C.) for the long distance transmission of electric power ?

    1 mark
  2. (ii)

    How is the type of current used in household supply different from the one given by a battery of dry cells ?

    1 mark
  3. (iii)

    How does an electric fuse prevent the electric circuit and the appliances from a possible damage due to short circuiting or overloading.

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Think of energy loss in transmission wires and whether the voltage can be changed.

Hint 2

Does the current from a cell ever change direction?

Hint 3

Fuse wire works on the heating effect of current. What happens to it when too much current flows?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (i) AC can be transmitted over long distances at high voltage without much loss of electrical energy. Its voltage can easily be stepped up or down, which DC cannot do easily.

    1 mark

  2. (ii) Household supply is alternating current (AC): its direction reverses periodically (50 Hz in India).

    ½ mark

  3. A battery of dry cells gives direct current (DC), which always flows in one direction.

    ½ mark

  4. (iii) A fuse is a wire of low melting point connected in series with the circuit. When the current exceeds its rating during a short circuit or overload, the fuse wire heats up, melts and breaks the circuit. This stops the current and protects the circuit and appliances.

    1 mark

Answer: (i) Less energy loss over long distances; (ii) Household: AC, dry cells: DC; (iii) Fuse melts on excess current and breaks the circuit

Where the marks are

  • AC transmitted over long distance with less energy loss (1 mark)
  • Household supply is AC (½ mark)
  • Battery gives DC (½ mark)
  • Fuse melts and breaks circuit when current exceeds rating (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Magnetic Effects of Electric Current, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 31/4/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.