SATHEE: Optics Question 82

Optics Question 82

Question: A thin rod of length $f / 3$ lies along the axis of a concave mirror of focal length $f .$ One end of its magnified image touches an end of the rod. The length of the image is

[MP PET 1995]

Options:

A) $f$

B) $\frac{1}{2} f$

C) $2 f$

D) $\frac{1}{4} f$

Show Answer

Answer:

Correct Answer: B

Solution:

If end A of rod acts an object for mirror then it’s image will be A’ and if $u = 2 f - \frac{f}{3} = \frac{5 f}{3}$ so by using $\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$

$\Rightarrow \frac{1}{- f} = \frac{1}{v} + \frac{1}{\frac{- 5 f}{3}}$

$\Rightarrow v = - \frac{5}{2} f$

$∴$ Length of image $= \frac{5}{2} f - 2 f = \frac{f}{2}$

Optics Question 82

Question: A thin rod of length $f / 3$ lies along the axis of a concave mirror of focal length $f .$ One end of its magnified image touches an end of the rod. The length of the image is

Options:

Answer:

Solution:

Engineering Preparation

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Optics Question 82

Question: A thin rod of length f/3 lies along the axis of a concave mirror of focal length f. One end of its magnified image touches an end of the rod. The length of the image is

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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Question: A thin rod of length $f / 3$ lies along the axis of a concave mirror of focal length $f .$ One end of its magnified image touches an end of the rod. The length of the image is