Go To Your Study Dashboard

Get Answers to all your Questions

header-bg

A concave mirror of focal length 'f₁' is placed at a distance of 'd' from a convex lens of focal length 'f2'. A beam of light coming from infinity and falling on this convex lens - concave mirror combination returns to infinity. The distance 'd' must equal:

Option 1)
f₁+f₂

Option 2)
-f₁+f₂

Option 3)
2f₁+f₂

Option 4)
-2f₁+f₂

Answers (1)

best_answer

First image will form at distance $f_{2}$ from lens.

For final image to return to infinity, the first image must be centre of curvature of mirror. Hence distance of image I from the mirror must be equal to $2f_{1}$

$\therefore d=2f_{1}+f_{2}$

Option 1)

f₁+f₂

This option is incorrect.

Option 2)

-f₁+f₂

This option is incorrect.

Option 3)

2f₁+f₂

This option is correct.

Option 4)

-2f₁+f₂

This option is incorrect.

Posted by

Aadil

View full answer

Similar Questions

Latest Question