Question

What is the wavelength of the light entering an interferometer if 402 bright fringes are counted when the movable mirror moves 0.115 mm?

Answer 1

The value is
`\lambda = 572 *10^(-9) \ m`

Step-by-step explanation:

From the question we are told that

The number of bright fringes is n = 402

The displacement of the mirror is
`\delta l = 0.115 \ mm = 1.15 *10^(-4) \ m`

Generally the number of fringes is mathematically represented as

`n = (2 * \delta l )/(\lambda )`

=>
`\lambda = (2 * \delta l )/(n )`

=>
`\lambda = (2 * 1.15*10^(-4) )/(402 )`

=>
`\lambda = 572 *10^(-9) \ m`