A screen is placed at a distance of 90 cm from an object. The image of this object is formed on the screen by a convex lens at two different location separated by 20cm. The focal length of the lens is

A screen is placed at a distance of 90 cm from an object. The image of

1.	A screen is placed at a distance of 90 cm from an object. The image of this object is formed on the screen by a convex lens at two different location separated by 20cm. The focal length of the lens is
Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :By the displacement method <br/> `f=(d^2-x^2)/(<a href="https://interviewquestions.tuteehub.com/tag/4d-318718" style="font-weight:bold;" target="_blank" title="Click to know more about 4D">4D</a>)= f=(90^2-20^2)/( 4 <a href="https://interviewquestions.tuteehub.com/tag/times-1420471" style="font-weight:bold;" target="_blank" title="Click to know more about TIMES">TIMES</a> 90)= 21.4 <a href="https://interviewquestions.tuteehub.com/tag/cm-919986" style="font-weight:bold;" target="_blank" title="Click to know more about CM">CM</a>`</body></html>