An image formed by a concave mirror of focal | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) For a concave mirror,the focal length $f = -6 \, cm$. The magnification $m = \pm 3$.Using the formula $m = \frac{f}{f - u}$,we have $\pm 3 = \frac

Vedclass · Accepted Answer

$-4$

Vedclass · Answer

(A) For a concave mirror,the focal length $f = -6 \, cm$. The magnification $m = \pm 3$.Using the formula $m = \frac{f}{f - u}$,we have $\pm 3 = \frac{-6}{-6 - u}$.Case $1$: For a real image,$m = -3$.$-3 = \frac{-6}{-6 - u} \implies -3(-6 - u) = -6 \implies 18 + 3u = -6 \implies 3u = -24 \implies u = -8 \, cm$.Case $2$: For a virtual image,$m = +3$.$3 = \frac{-6}{-6 - u} \implies 3(-6 - u) = -6 \implies -18 - 3u = -6 \implies -3u = 12 \implies u = -4 \, cm$.Thus,the possible distances of the object from the mirror are $4 \, cm$ or $8 \, cm$.

An image formed by a concave mirror of focal length $6 \, cm$ is $3$ times the size of the object. The distance of the object from the mirror is......$cm$.

Similar Questions

You are asked to design a shaving mirror assuming that a person keeps it $10\,cm$ from his face and views the magnified image of the face at the closest comfortable distance of $25\,cm$. The radius of curvature of the mirror would then be.....$cm$.

$A$ person sees his virtual image by holding a mirror very close to the face. When he moves the mirror away from his face,the image becomes inverted. What type of mirror is he using?

An object ' $O$ ' is placed at a distance of $100\,cm$ in front of a concave mirror of radius of curvature $200\,cm$ as shown in the figure. The object starts moving towards the mirror at a speed of $2\,cm/s$. The position of the image from the mirror after $10\,s$ will be at ...... $cm$.

The circular boundary of the concave mirror subtends a cone of half-angle $\theta$ at its centre of curvature. The minimum value of $\theta$ for which a ray incident on this mirror parallel to the principal axis suffers more than one reflection is......$^o$

An object is placed $40\;cm$ from a concave mirror of focal length $20\;cm.$ The image formed is

Vedclass Test Series

Exam Paper Generator

Online Exam Module