In an experiment for the determination of focal length of a convex mirror,a convex lens of focal length $20 \ cm$ is placed on an optical bench and an object pin is placed at a distance $30 \ cm$ from the lens. When a convex mirror is introduced in between the lens and the real and inverted image of the object,the final image of the object $O$ is formed at $O$ itself. If the distance between the lens and the mirror is $10 \ cm$,then the focal length of the mirror is.......$cm$

  • A
    $10$
  • B
    $20$
  • C
    $25$
  • D
    $50$

Explore More

Similar Questions

An object is placed in front of a convex mirror at a distance of $50\, cm$. $A$ plane mirror is introduced covering the lower half of the convex mirror. If the distance between the object and the plane mirror is $30\, cm$,it is found that there is no parallax between the images formed by the two mirrors. The magnification of the convex mirror will be......

Difficult
View Solution

Which of the following is $NOT$ involved in the formation of a secondary rainbow?

Column-$I$ contains a list of mirrors and positions of an object. Match this with Column-$II$ describing the nature of the image formed.

Ray optics is valid when characteristic dimensions are:

An optical bench has a $1.5 m$ long scale having four equal divisions in each $cm$. While measuring the focal length of a convex lens,the lens is kept at the $75 cm$ mark of the scale and the object pin is kept at the $45 cm$ mark. The image of the object pin on the other side of the lens overlaps with the image pin that is kept at the $135 cm$ mark. In this experiment,the percentage error in the measurement of the focal length of the lens is. . . . .

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo