In: Physics
An object is placed 68cm from a screen
1. At what point from the object should a converging lens with a focal length of 17cm be placed so that it will produce a sharp image on the screen? (in cm from the object)
2. What is the image's magnification?
The distance from the screen to the object is,]
u + v = 68
The thin lens equation is,
1/f = 1/u +1/v
f = uv/(u+v)
= uv/68
Then, we get
uv = 68*f = 68*17 = 1156
sop (u-v)^2 = (u+v)^2 -4uv
(u-v)^2 = 68*68-(4*1156)
u -v = 0
u =v
as u+v = 68
2u = 68
= 34 cm
and v = 34 cm
magnification m = -v/u = -1