The image distance is -7.19 cm, and the linear magnification is 0.37
To find the image distance and linear magnification for a small object on the optical axis, 19.3 cm from a lens of focal length −11 cm, we must use the thin lens equation and the magnification equation.
The thin lens equation is 1/f = 1/do + 1/di
Such that;
- f is the focal length
- do is the object distance
- di is the image distance.
Then, we have;
di, yielding di = 1/(1/f - 1/do).
Substitute the values, we get;
(f = -11 cm and do=19.3 cm),
Image distance, di = 1/(1/-11 - 1/19.3) = -7.19 cm.
To find the linear magnification m, we use the equation;
m = -di/do
Substitute the values, we have;
m = -(-7.19)/19.3 = 0.37.