Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Ray Optics

Question:

A Convex mirror produces the magnification 1/3 and 1/4 when the object is placed at the points P and Q in front of the mirror.

Options:

P is far from the mirror as compared to Q

Q is far from the mirror as compared to P

P and Q both are coinciding

Convex mirror produces the magnification always greater than 1

Correct Answer:

Q is far from the mirror as compared to P

Explanation:

Let object distance is u .

Magnification m = \frac{-v}{u} = \frac{1}{3}$

$\Rightarrow v = \frac{-u}{3}$

Mirror formula is $\Rightarrow \frac{1}{v} + \frac{1}{u} = \frac{1}{f}$

$ \frac{-3}{u} + \frac{1}{u} = \frac{1}{f} \Rightarrow u = -2f$

If Magnification is $\frac{1}{4}$ then from similar method u' = -3f$

⇒ Q is far from the mirror as compared to P