A lens is placed between a source of light and a wall. It forms images of area A 1 and A2 on the wall, for its two different positions. The area of the source of light is

Question

A lens is placed between a source of light and a wall. It forms images of area A 1 and A2 on the wall, for its two different positions. The area of the source of light is (A) (A1-A2/2) (B)  (1/A1) - (1/A2) (C) √A1 A2 (D) (A1+A2/2)

Tardigrade Admin · Accepted Answer

By displacement method, size of object (O) = √I1 × I2 Therefore area of source of light (A) = √A1 A2

Q. A lens is placed between a source of light and a wall. It forms images of area $A_{1}$ and $A_{2}$ on the wall, for its two different positions. The area of the source of light is

$\frac{A _{1} - A _{2}}{2}$

$\frac{1}{A _{1}} - \frac{1}{A _{2}}$

$A_{1} A_{2}$

$\frac{A _{1} + A _{2}}{2}$

By displacement method, size of object
$(O) = I_{1} \times I_{2}$
Therefore area of source of light (A) = $A_{1} A_{2}$

Q. A lens is placed between a source of light and a wall. It forms images of area A1​ and A2​ on the wall, for its two different positions. The area of the source of light is

2A1​−A2​​

A1​1​−A2​1​

A1​A2​​

2A1​+A2​​