Question

A prism of small angle 'A' and refractive index $\mu$ is placed in front of lens of focal length 'f' as shown in figure. A point is placed at origin. Then for rays refracted from both prism and lens,

• A. Virtual image of object is formed
• B. x-coordinate of image is 3f
• C. y-coordinate of image is $-2f(\mu -1)A$
• D. Real image of object is formed

Answer 1

Answer: (C), (D)

The correct options are
C y-coordinate of image is $-2f(\mu -1)A$
D Real image of object is formed


$\delta =(\mu -1)A$

By $\delta =\frac{h}{f}\Rightarrow h=f\delta$

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

and $\frac{I}{h}=\frac{v}{u}\Rightarrow I=-2f\delta$

so x-coordinate is

$\frac{3}{2}f+3f=\frac{9}{2}f=4.5f$

and y-coordinate is

$h^{{}^{\prime }}=-2f\delta$