The size of the images of an object,formed by | vedclass

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

Question

(B) For a thin lens,the magnification $m$ is given by $m = \frac{f}{f+u}$.Since the sizes of the images are equal,the magnitude of magnification must

Vedclass · Accepted Answer

$16$

Vedclass · Answer

(B) For a thin lens,the magnification $m$ is given by $m = \frac{f}{f+u}$.Since the sizes of the images are equal,the magnitude of magnification must be the same,but one image is real (inverted) and the other is virtual (erect).Thus,$m_1 = -m_2$.Let the two positions be $u_1 = -8 \ cm$ and $u_2 = -24 \ cm$.Substituting these into the magnification formula: $\frac{f}{f-8} = -\frac{f}{f-24}$.Canceling $f$ from both sides (assuming $f 
eq 0$): $\frac{1}{f-8} = -\frac{1}{f-24}$.Cross-multiplying gives: $f - 24 = -(f - 8)$.$f - 24 = -f + 8$.$2f = 32$.$f = 16 \ cm$.

The size of the images of an object,formed by a thin lens,are equal when the object is placed at two different positions $8 \ cm$ and $24 \ cm$ from the lens. The focal length of the lens is . . . . . . $cm$.

Similar Questions

An object of height $1.5 \ cm$ is placed on the axis of a convex lens of focal length $25 \ cm$. $A$ real image is formed at a distance of $75 \ cm$ from the lens. The size of the image will be........$cm$.

$A$ convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens material. Then its focal length will

$A$ point object is moving at a constant speed of $1 \,ms^{-1}$ along the principal axis of a convex lens of focal length $10 \,cm$. The speed of the image is also $1 \,ms^{-1}$, when the object is at what distance (in $cm$) from the optical centre of the lens?

In the diagram shown,the lens is moving towards the object with a velocity $V \, m/s$ and the object is also moving towards the lens with the same speed. What is the speed of the image with respect to the earth when the object is at a distance $2f$ from the lens? ($f$ is the focal length.)

$A$ biconvex lens has a focal length $2/3$ times the radius of curvature of either surface. The refractive index of the material is:

Vedclass Test Series

Exam Paper Generator

Online Exam Module