The graph shows how the magnification m produced by a thin lens varies with image distance v . The focal length of the lens used is

Question

The graph shows how the magnification m produced by a thin lens varies with image distance v . The focal length of the lens used is <img class="img-fluid question-image" alt="Question" src="https://cdn.tardigrade.in/q/nta/p-7vgufnfpok7l.png" /> (A) (b/c) (B) (a/c) (C) (b2 c/a) (D) (b2/a c)

Tardigrade Admin · Accepted Answer

For a thin lens, |m|=|1 - (v/f)| From the graph, slope of the line m=(1/f) (c/b)=(1/f) f=(b/c)

Q. The graph shows how the magnification $m$ produced by a thin lens varies with image distance $v$ . The focal length of the lens used is

$\frac{b}{c}$

$\frac{a}{c}$

$\frac{b ^{2} c}{a}$

$\frac{b ^{2}}{a c}$

For a thin lens,
$∣ m ∣ = ∣ ∣ 1 - \frac{v}{f} ∣ ∣$
From the graph, slope of the line $m = \frac{1}{f}$
$\frac{c}{b} = \frac{1}{f}$
$f = \frac{b}{c}$

Q. The graph shows how the magnification m produced by a thin lens varies with image distance v . The focal length of the lens used is

cb​

ca​

ab2c​

acb2​