Physics - Geometrical Optics Question with Solution | TestHub

$\mathrm{\pi }{r}^2\propto f$

$\mathrm{\pi }r²\propto f^2$

If lower half part is covered by black sheet, then area of the image is equal to$\frac{\pi r^2}{2}$

If$\mathrm{f }$is doubled, intensity will increase