Question

A film projector magnifies a $ 100\,c{{m}^{2}} $ film strip on a screen. If the linear magnification is $4$, the area of the magnified film on the screen is:

• A. $ 1600\,c{{m}^{2}} $
• B. $ 400\,c{{m}^{2}} $
• C. $ 800\,c{{m}^{2}} $
• D. $ 200\,c{{m}^{2}} $

Answer 1

Answer: (A)

Linear magnification $=4$
Areal magnification $=\text { (linear magnification) }^{2} $
$=(4)^{2}=16$
Therefore, area of magnified flim on the screen
$=$ areal magnification $\times$ area
$=16 \times 100 $
$=1600 \,cm ^{2}$