Question

A parallel beam of light is incident on lens mirror combination as shown in figure, then after reflection from mirror

• A. x-cordinate where beam converges is $\frac{-5\sqrt{3}}{2}$ cm
• B. y-cordinate where beam converges is 5 cm
• C. Beam diverges after reflection from mirror
• D. Beam converges after reflection from mirror

Answer 1

Answer: (A), (D)

The correct options are
A x-cordinate where beam converges is $\frac{-5\sqrt{3}}{2}$ cm
D Beam converges after reflection from mirror

By $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\Rightarrow \frac{1}{20}=\frac{1}{v}-\frac{1}{\infty }\Rightarrow v=20cm$
Because of refraction image is supposed to form 5 cm behind the mirror, which will act as object for reflection and image will be formed at P as shown.