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A positron enters a uniform… (Class 10 Science 2023, Q16)

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ScienceCBSE Class 10 · Board exam 2023, set 31/2/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 16

Set in the CBSE Class 10 board exam of 2023, paper 31/2/1, section A, question 16, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q16 · 1 mark · MCQMagnetic Effects of Electric Current

A positron enters a uniform magnetic field at right angles to it as shown. The direction of force experienced by the positron will be :

  1. (A)to the right
  2. (B)to the left
  3. (C)into the page
  4. (D)out of the page

Figure in the paper: A vertical arrow labelled 'Positron' pointing upward, and four horizontal parallel arrows pointing to the right, labelled 'Magnetic field'. The positron moves upward across the horizontal field lines at right angles to them. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/2/1.

Hints

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

Hint 1

A positron behaves like a positive charge, so current is along its motion.

Hint 2

Use Fleming's left-hand rule.

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. A positron carries positive charge, so the current is in its direction of motion (upward). The field points to the right.

  2. By Fleming's left-hand rule (field to the right, current upward), the thumb points into the page.

    1 mark

Answer: (C) into the page

Where the marks are

  • Applies Fleming's left-hand rule to get into the page (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 31/2/1: 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.