Question

A lens is used to make an image of magnification -1.50. The image is 30.0 cm from the lens. What is the object’s distance (unit=cm)? pls help

Answer 1

Answer:

The object distance is 20cm

Explanation:

Given

Magnification = -1.5

Image distance = 30 cm.

Required

Object Distance

We can calculate the object's distance using magnification formula;

M = -V/U

Where M = Magnification = -1.50

V = Image Distance = 30cm

U = Object Distance

Substitute the above parameters in the formula above.

-1.50 = -30/U

Multiply both sides by -1

-1.50 * -1 = -30/U * -1

1.50 = 30/U

Multiply both sides by U

1.50 * U = 30/U * U

1.50U = 30

Divide through by 1.50

1.50U/1.50 = 30/1.50

U = 30/1.50

U = 20cm

Recall that U represented the object distance.

Hence, the object distance is 20cm