I f we look at the derivation of the mirror formulae using similarity of triangles, we find that magnification is equal to v/u then why the hell do we write -v/u. From where does this minus sign come?

Asked by vasundhra | 15th Dec, 2013, 10:35: AM

Expert Answer:

Geometry is a mathematical concept. We need to deal with the physics too. Hence, when we derive the formula, we take into consideration the sign conventions that are developed for forming images by spherical mirrors.
 
Hence, the formula after applying sign convention comes out to be m = -v/u.
 

Answered by Romal Bhansali | 16th Dec, 2013, 03:20: PM

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