Question

Class X Sciences
[papers from previous years]

A student has obtained an image of a well-illuminated distant
object on a screen to determine the focal length, F1 of
the given spherical mirror. The teacher then gave him another
mirror of focal length, F2 and asked him to obtain a
focussed image of the same object on the same screen. The student
found that in order to focus the same object using the second
mirror, he has to move the mirror away from the screen. From this
observation it may be concluded that both the spherical mirrors
given to the student were (select the correct option)
(A) Concave and F1 < F2
(B) Concave and F1 > F2
(C) Convex and F1 < F2
(D) Convex and F1 > F2

Answer 1

Both are concave and F1 < F2.
So (A) is the answer.