Question

The object distance for a concave lens is 8.0 cm, and the image distance is 12.0 cm. The height of the object is 4.0 cm. What is the height of the image?

0.50 cm
2.7 cm
18 cm
6.0 cm

Answer 1

The answer for this question, If I am correct, should be answer "D".

Answer 2

So we want to know the height Hi of the image if we know object distance Do=8 cm, image distance Di= 12 cm and the height of the object H0= 4 cm. The magnification formula is M=(Hi/H0)=(Di/Do). By multiplying the equation with H0 we get Hi=(Di/Do)*H0. Now we input the numbers and get: Hi=(12/8)*4=6 cm. So the height of the image Hi=6 cm.