A point source of light S is placed at distance $$10$$ cm from the pole of a convex mirror of local length $$10$$ cm. The intensity of light at the center of screen in the absence of mirror is $$49Wm$$−$$2$$ . Find the intensity of light on screen in the presence of mirror.

Question

A point source of light S is placed at distance $$10$$ cm from the pole of a convex mirror of local length $$10$$ cm. The intensity of light at the center of screen in the absence of mirror is $$49Wm$$−$$2$$ . Find the intensity of light on screen in the presence of mirror.

Infinity Learn · Accepted Answer

Here, Intensity without mirror is   $$I0=Po4$$$$π$$$$0.22where$$ $$P0$$ is power of source. The intensity at the side of mirror is  $$I=P04$$$$π$$$$0.12=I04$$$$π$$$$0.224$$$$π$$$$0.12=4I0The$$ power of incident on mirror is $$Pm=$$π$$d24$$×$$4I0=$$π$$d2I0Here$$, d is aperture of mirror, ∵$$u=$$−$$10cm$$,$$f=+10cm$$ ∵$$1v+1u=1f$$ ∴$$v=5$$ cmFrom similar triangles, $$Dd=355$$ ∴$$D=7dIntensity$$ due to reflected light on the screen is $$I1=4Pm$$$$π$$$$7d2=4$$$$π$$$$d2I0$$$$π$$$$49d2=4I049Total$$ intensity $$=$$  $$I0+4I049=53I049$$                               $$=53$$×$$4949=53$$ Wm−$$2$$

A point source of light S is placed at distance 10 cm from the pole of a convex mirror of local length 10 cm. The intensity of light at the center of screen in the absence of mirror is $49 W m^{- 2}$ . Find the intensity of light on screen in the presence of mirror.

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A point source of light S is placed at distance 10 cm from the pole of a convex mirror of local length 10 cm. The intensity of light at the center of screen in the absence of mirror is 49Wm−2 . Find the intensity of light on screen in the presence of mirror.

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A point source of light S is placed at distance 10 cm from the pole of a convex mirror of local length 10 cm. The intensity of light at the center of screen in the absence of mirror is $49 W m^{- 2}$ . Find the intensity of light on screen in the presence of mirror.