Student Login

Home›Chapters›Ray Optics PYQs›Reflection & Mirrors›Question 40

JEE Main 2020 (3 Sep, Shift 2) · Reflection & Mirrors

Reflection & Mirrors question from JEE Main 2020 (3 Sep, Shift 2)

Q40JEE Main 2020 · 3 SEP · SHIFT 2Medium

Reflection & Mirrors

When an object is kept at a distance of 30 cm from a concave mirror, the image is formed at a distance of 10 cm from the mirror. If the object is moved with a speed of 9 cms–1, the speed (in cms–1) with which image moves at that instant is ____.

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 1

For a mirror, image speed along the axis: $v_I = \frac{v^2}{u^2}\, v_O$ (in magnitude).
$v_I = \left(\frac{10}{30}\right)^2 \times 9 = \frac{1}{9} \times 9$
So the image moves at $1\text{ cm s}^{-1}$ .

Report a mistake

More questions on Reflection & Mirrors

A concave mirror for face viewing has focal length of 0.4 m. The distance at which you…JEE Main 2019 (9 Apr, Shift 1)
Two plane mirrors are inclined to each other such that a ray of light incident on the…JEE Main 2019 (9 Jan, Shift 2)
A point source of light, S is placed at distance L in front of the centre of plane mirror…JEE Main 2019 (12 Jan, Shift 1)
An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm…NEET 2018
A particle is oscillating on the X -axis with an amplitude 2 cm about the point x₀ = 10…JEE Main 2018 (15 Apr, Shift 1)
A beam of light from a source L is incident normally on a plane mirror fixed at a certain…NEET 2017
Match the corresponding entries of column 1 with column 2. [Where m is the magnification…NEET 2016 (Phase 1)
You are asked to design a shaving mirror assuming that a person keeps it 10 cm from his…JEE Main 2015 (10 Apr, Shift 1)