Question

calculate degree of non monochromaticity for wavelength 5000 A° if coherence time is 10^-10 sec​

Answer 1

Explanation:

Monochromaticity. The energy of a photon determines its wavelength through the relationship E = hc/λ, where c is the speed of light, h is Planck's constant, and λ is wavelength. In an ideal case, the laser emits all photons with the same energy, and thus the same wavelength, it is said to be monochromatic.

Answer 2

Concept

The term "monochromatic" refers to a laser's output having only one wavelength overall. All visible wavelengths are combined to create white light ($400 - 700 nm$). When a light beam is directional, it has extremely little divergence.

Given

Wavelength $5000$ A° if coherence time is $10^{-10} sec$

To Find

We have to find the monochromaticity.

Solution

According to the problem,

To elaborate: Coherence time,$t = 10^{-10} s$

Therefore, Δv $= 1/t = 10^{10} Hz$

Now,  λo = $5000$ Å, vo = $5.0 X 10^{14} Hz$

Monochromaticity = Δv/v0

$=10^{10} /5*10^{14}$

$=0.2*10^{-4}$

Hence, monochromaticity is $=0.2*10^{-4}$.

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