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

Question

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

Infinity Learn · Accepted Answer

Let say the length and breadth of object is a and b .Area of object  $$=$$ a × b   In first position of displacement method,   Area of $$Image1$$ , $$A1=$$ $$m1a$$×$$m1b$$ → (1)In$$ second  position of displacement method,   Area of $$Image2$$ , $$A2=$$ $$m2a$$×$$m2b$$ → $$(2) Multiply equation $$1$$ and $$2$$  $$A1A2$$ $$=$$ $$(m1m2)2$$ $$(ab)2Also$$, in displcement method , $$m1m2$$ $$=$$ $$1$$   ⇒$$A1A2$$ $$=$$ $$(ab)2$$⇒ab  $$=A1A2$$ ⇒Area of object $$=$$ $$A1A2$$

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

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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

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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