A real object is 42 cm from a negative lens with f = -21 cm.The image is
A)real and 14 cm from the lens.
B)real and 42 cm from the lens.
C)virtual and 42 cm from the lens.
D)virtual and 21 cm from the lens.
E)virtual and 14 cm from the lens.

Question

Quizplus · Accepted Answer

Using the lens formula 1/f = 1/v - 1/u, where f is the focal length, v is the image distance, and u is the object distance. Substituting f = -21 cm and u = -42 cm (since the object is on the opposite side of the light's direction, it's considered negative), we solve for v. The calculation shows the image is virtual and 14 cm from the lens on the same side as the object.

A Real Object Is 42 Cm from a Negative Lens