Physics quiz question: real image with greatest magnification

Physics 205B Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Placing an object __________ to the left of a converging lens would produce a real image with the greatest magnification.
(A) out at ∞.
(B) just outside the focal length.
(C) just inside the focal length.
(D) almost next to the lens.

Correct answer: (B)

In order to produce a real image from a converging lens, an object should be placed at a distance anywhere from +f < p < +∞. As linear magnification m = -q/p = f/(f - p), the greatest magnified real image will result in the limit where p -> f.

Response (C) would result in a virtual image with the greatest magnification.

Section 30882
Exam code: quiz02gL4s
(A) : 1 student
(B) : 18 students
(C) : 5 students
(D) : 0 students

Success level: 75%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.47