Question

Band width for red light of wavelength 6600 Å is 0.42 mm. If red Light is replaced by blue light of wavelength 4400 Å, then the change m bandwidth will be ____________.

Options

• 21 x 10^-6 m

• 21 x 10^-5 m

• 4 x 10^-6 m

• 4 x 10^-5 m

Answer 1

Band width for red light of wavelength 6600 Å is 0.42 mm. If red Light is replaced by blue light of wavelength 4400 Å, then the change m bandwidth will be 21 x 10^-5 m.

Explanation:

`"W" prop lambda`

`therefore "W"_2/"W"_1 = lambda_2/lambda _1 Rightarrow "W"_2 = "W"_1 xx lambda_2/lambda_1`

`= 0.32 xx 4400/6600`

` = 0.21 "mm"`

`therefore "Change in W" = 0.42 - 0.21`

`= 0.21 "mm"`

`= 21 xx 10^-5  "m"`