How can the focal length of a concave mirror determined?

Discussion in 'CBSE Class 10 Physics Help' started by Vinila Choudary, Jan 19, 2012.

  1. Vinila Choudary

    Vinila Choudary Active Member

    Hold a concave mirror in your hand and point its reflecting surface towards a tree or a distant building. Now put a piece of white cardboard between the mirror and the object. Move the cardboard or the mirror until a sharp inverted image of the tree or building is formed on the cardboard. The position of the cardboard where the image is the sharpest and brightest is the focal plane. Measure the distance between the mirror and the cardboard with a ruler. It is the focal length of the concave mirror. Repeat the activity several times to obtain several values focal length and calculate the average value.

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