Question

What will be the focal length of convex lens when an image is formed at a distance of 75cm and object is 25cm away

Answer 1

Question:

What will be the focal length of convex lens when an image is formed at a distance of 75cm and object is 25cm away ?

_________________________________

Answer:

given,

• object distance U = – 25cm
• image distance V = 75cm
• focal length f = ?

Lens formula,

$\frac{1}{f } = \frac{1}{v} - \frac{1}{u}$

put given values in formula,

$\frac{1}{f} = \frac{1}{75} + \frac{1}{25} = \frac{1 + 3}{75} \\ \\ f = + 18.75cm$

So, focal length is 18.75 cm of convex lens.

_________________________________

_________________________________

Hope it helps you...✌✌