John's face is 20 cm in front of a concave shaving mirror. If he observes his image to be twice as big and erect, what is the focal length of the mirror?
A) 10 cm
B) 20 cm
C) 30 cm
D) 40 cm
E) 50 cm

Question

Quizplus · Accepted Answer

The Answer of John's face is 20 cm in front of a concave shaving mirror. If he observes his image to be twice as big and erect, what is the focal length of the mirror?
A) 10 cm
B) 20 cm
C) 30 cm
D) 40 cm
E) 50 cm

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