A diverging lens of focal length f1 is placed infront of and coaxially with a concave mirror of focal length f2 . The separation between the lens and the mirror is d. A parallel beam of light incident on the lens returns as a parallel beam from the arrangement.

Question

A diverging lens of focal length f1 is placed infront of and coaxially with a concave mirror of focal length f2 . The separation between the lens and the mirror is d. A parallel beam of light incident on the lens returns as a parallel beam from the arrangement. (A) The beam diameter of the incident and reflected beams will not be same. (B) d=2|f2|-|f1| (C) If the entire arrangement is immersed in water, the conditions will remains unaltered. (D) none of the above

Tardigrade Admin · Accepted Answer

(d + |f1|)=2|f2| ⇒ d=2|f2|-|f1| <img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/p-jmcu36ir9a2n3f4v.jpg" />

Q. A diverging lens of focal length $f_{1}$ is placed infront of and coaxially with a concave mirror of focal length $f_{2}$ . The separation between the lens and the mirror is $d .$ A parallel beam of light incident on the lens returns as a parallel beam from the arrangement.

The beam diameter of the incident and reflected beams will not be same.

$d = 2 ∣ f_{2} ∣ - ∣ f_{1} ∣$

If the entire arrangement is immersed in water, the conditions will remains unaltered.

none of the above

$(d + ∣ f_{1} ∣) = 2 ∣ f_{2} ∣$
$\Rightarrow d = 2 ∣ f_{2} ∣ - ∣ f_{1} ∣$

Q. A diverging lens of focal length f1​ is placed infront of and coaxially with a concave mirror of focal length f2​ . The separation between the lens and the mirror is d. A parallel beam of light incident on the lens returns as a parallel beam from the arrangement.