The candle light source is at the 10 cm mark of the optical bench. A concave mirror of focal length 20 cm is used. The mirror position is adjusted infront of the candle until at 40 cm mark, a sharp and distinct image is seen on the screen. At what distance from the candle must the screen be placed so as to produce a sharp image on the screen? Describe the image formed on the screen. (nature,orientation, and size).

Question

sharmagk83 · Answer

Distance of the object from the mirror = 40 cm - 10 cm = 30 cm
So u = -30 cm, f = -20 cm
Using mirror equation
$$\frac{ 1 }{f }= \frac{ 1 }{ u }+\frac{ 1 }{ v }$$
$$\frac{ 1 }{ v }= \frac{ 1 }{ f }-\frac{ 1 }{ u }$$
$$v = \frac{ uf }{ u-f }$$
$$v = \frac{ -30\times(-20) }{ -30+20 }$$
$$v = -60 cm$$
So image will be real, inverted and enlarged.

snitchseeker1496 · Answer

@sharmagk83 thank you for helping me :)