The focal length of a convex lens is f. An ob | vedclass

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

Question

(C) The focal length of the convex lens is given as $f$. The object is placed at a distance $x$ from the first focal point. Since the first focal poin

Vedclass · Accepted Answer

$\frac{f}{x}$

Vedclass · Answer

(C) The focal length of the convex lens is given as $f$. The object is placed at a distance $x$ from the first focal point. Since the first focal point is at a distance $f$ from the optical center,the total object distance $u$ from the optical center is $u = -(f + x)$. Using the lens formula,$\frac{1}{v} - \frac{1}{u} = \frac{1}{f}$. Substituting $u = -(f + x)$,we get $\frac{1}{v} - \frac{1}{-(f + x)} = \frac{1}{f}$. $\frac{1}{v} = \frac{1}{f} - \frac{1}{f + x} = \frac{f + x - f}{f(f + x)} = \frac{x}{f(f + x)}$. Thus,$v = \frac{f(f + x)}{x}$. The magnification $m$ is given by $m = \frac{v}{u}$. $m = \frac{\frac{f(f + x)}{x}}{-(f + x)} = -\frac{f}{x}$. The ratio of the size of the real image to the object is the magnitude of magnification,which is $|m| = \frac{f}{x}$.

The focal length of a convex lens is $f$. An object is placed at a distance $x$ from its first focal point. The ratio of the size of the real image to that of the object is

Similar Questions

Where should an object be placed on the axis of a convex lens of focal length $8 \ cm$ so as to achieve magnification of $-4$ (in $cm$)? (Distances are measured from the optic centre of the lens)

$A$ double convex lens of glass of $\mu = 1.5$ has a radius of curvature of each of its surfaces equal to $0.2 \ m$. The power of the lens is:

An object is placed at a distance of $5 \, cm$ from the first principal focus of a convex lens of focal length $10 \, cm$. If a real image is formed,find its distance from the lens in $cm$.

$A$ lens of focal power $0.5 D$ is

The distance between an object and its image produced by a converging lens is $0.72 \ m$. The magnification is $2$. What will be the magnification when the object is moved by $0.04 \ m$ towards the lens?

Vedclass Test Series

Exam Paper Generator

Online Exam Module