A point light sources lies on the principal axis of concave spherical mirror with radius of curvature 160cm. Its image appears to the back of the mirror at a distance of 70 cm from mirror. Determine the location of the light source.

A point light sources lies on the principal axis of concave spherical

1.	A point light sources lies on the principal axis of concave spherical mirror with radius of curvature 160cm. Its image appears to the back of the mirror at a distance of 70 cm from mirror. Determine the location of the light source.
Answer» Solution :`1/u+1/v=2/R` Here v=70 CM `R=-160 cm 1/u=2/R-1/v` `therefore 1/u=2/(-160CM)-1/(70CM) =-15/(560cm)` `therefore u= -560/15 cm=-37cm` The source is at a DISTANCE of 37 cm in front of the mirror.