Question

The image of a distant object is obtained on a screen by using a concave mirror. The focal length of the mirror can be determined by measuring the distance between



A)the object and the mirror

B)the object and the screen

C)the mirror and the screen

D)the mirror and the screen as well as that between the object and the screen

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Answer 1

Take the distant object to be at infinity

Then the image formed will be point-sized and at the focus

Since the image is formed on the screen, the screen and focus must be the same point

Thus the answer should be :

C)the mirror and the screen