0

Guest

Courses New

A beam of light converges at a point P.Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge, if the lens is (i)A convex lens of focal length 20cm. (ii) A concave lens of focal length=16cm ?

A beam of light converges at a point P.Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge, if the lens is (i)A convex lens of focal length 20cm. (ii) A concave lens of focal length=16cm ?

Grade:12th pass

1 Answers

Arun
25750 Points
6 years ago
Dear Nikita
Object distance, u = +12 cm (virtual object)
(a) Focal length of the convex lens, f = 20 cm
     Image distance = v
     Applying lens formula
     1/v – 1/u = 1/f
     Therefore putting the values and solving the equation, we get v = 60/8 i.e. = 7.5 cm
     Hence, the image is formed 7.5 cm away from the lens, toward its right.
(b) Focal length of the concave lens, f = -16
     again image distance = v
     the again as previous, applying the lens formula, substituing the values of u and f, we get v= 48 cm.
     Hence, the image is formed 48 cm away from the lens, towards its right.
Regards
Arun (askIITians forum expert)

Think You Can Provide A Better Answer ?

Other Related Questions on IIT JEE Entrance Exam

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More