Question

a 50m high object was seen via a telescope 100m from a 3.5mm focal length converging lens. Determine the image distance, magnification, and object height

Answer 1

Gives

$Object distance (o)=$ 100m

Focal length (d)=3.5mm

We know that

$$\frac{1}{o}+\frac{1}{I}=\frac{1}{f}$$

Put value

$\frac{1}{I}=\frac{1}{3.5\times10^{-3}}-\frac{1}{100}$

Object distance $d_I=3.5\times10^{-3}m$

Magnificent

$m=\frac{I}{o}$

Put value

$m=\frac{3.5\times10^{-3}}{100}$

$m=3.5\times10^{-5}$

Object hight

$\frac{I}{o}=\frac{h}{h'}$

$h'=\frac{I}{o}\times h$

Put value

$h'=\frac{50}{100}\times3.5\times10^{-3}$

$h'=1.75\times10^{-3}m$

$h'=1.75mm$