An object 4 cm high is placed 15 cm in front of a convex mirror with a focal length of −10 cm. What is the image position (in cm)?
A) −8
B) −4
C) −2
D) −6
E) 30

Question

Quizplus · Accepted Answer

By the mirror formula: 
1/f = 1/p + 1/q 
where f is the focal length, p is the object distance and q is the image distance.
Substituting the given values, we get: 
1/-10 = 1/15 + 1/q 
Solving for q, we get: 
q = -6 cm 
Therefore, the image position is -6 cm. The correct choice is D.

An Object 4 Cm High Is Placed 15 Cm in Front