Question

determine of the focal length of :.
1 concave mirror
2 convex lens
by obtaining the image of a distant object
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Answer 1

Answer:

1) Place the screen in front of the reflecting surface of the mirror. Move the screen back and forth until a clear, sharp image of the distant object is obtained on the screen. Measure the distance between the concave mirror and the screen with a metre scale. This distance is the focal length of the given concave mirror.

2) Place the holder with the screen on the bench. The position of the screen should be such that the sharp image of the distant object is obtained on it. The difference between the position of the lens and the screen is equal to the focal length of the given convex lens.