Reflecting Power Mirrors Homework Help, Assignment Help, Online Tutor, Tutoring

Submit Assignment

* *

Payment Online Assignment Help

Thermodynamics

Homework Help

sfsf

Reflecting Power Mirrors

The reflecting power of mirrors can be determined with the help of Lummer-Brodhum and Bunsen photometers. A source S is placed at a distance R from the screen and another source S₁ is placed at such a suitable distance from the screen so that the photometric balance is obtained. Suppose the distance of the source S₁ from the screen is R₁. If L and L₁ are the illuminating powers of the sources S and S₁

Now the mirror M is inclined at an angle of 45˚ to the line joining AB and the source S is brought to a point A’.

By moving M and the source S together, a position is found where photometric balance is obtained. Suppose in this position, the distance of the mirror from the screen = and the distance of the source S from M = b.

If r is the reflecting power of the mirror, then in this case L’ = rL i.e. light reflected from M can be considered to be due to a source of reduced illuminating power L’

From equations (i) and (ii)

As a, b and R are all measurable quantities r can be calculated.