Question

The focal length F of a lens made by combining two lenses of focal length U and V is given I/F=I/U+I/V

Answer 1

Answer:

a). $V=\frac{U.F}{U-F}$

b). V = 15 units

Step-by-step explanation:

Focal length F of a lens made by combining two lenses of different focal lengths U and V will be,

$\frac{1}{F}=\frac{1}{U}+\frac{1}{V}$

A). By solving the given formula,

    $\frac{1}{V}=\frac{1}{F}-\frac{1}{U}$

    $\frac{1}{V}=\frac{U-F}{U.F}$

    $V=\frac{U.F}{U-F}$

B). If F = 6 and U = 10 then we have to find the value of V.

    By substituting the given values in the formula,

    $V=\frac{6\times 10}{10-6}$

    $V=\frac{60}{4}$

    V = 15 units

    Therefore, focal length (V) of the lens = 15 units