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