John's Face Is 20 Cm in Front of a Concave

Multiple Choice

John's face is 20 cm in front of a concave shaving mirror of focal length 30 cm. How large an image does he observe?

A) half as large as his face
B) of the same size as his face
C) twice as large as his face
D) three times as large as his face
E) four times as large as his face