A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be____________
A. –10 cm
B. –15 cm
C. –20 cm
D. –30 cm
Answer:B
A concave mirror gives an image three times as large as the object placed at a distance of 20 cm from it. For the image to be real, the focal length should be____________
A. –10 cm B. –15 cm C. –20 cm D. –30 cm