Q10Engineering Physics

Question

Numerical: Wavefront overlapping by 40%, find visibility.

Answer 1

In interference, the visibility $V$ of fringes is related to the degree of partial coherence $∣ γ_{12} ∣$ by:

V = \frac{2 I _{1} I _{2}}{I _{1} + I _{2}} ∣ γ_{12} ∣

Assuming the intensities of the two interfering wavefronts are equal ( $I_{1} = I_{2}$ ), the factor $\frac{2 I _{1} I _{2}}{I _{1} + I _{2}}$ becomes $1$ .

Given that the wavefront overlap (degree of coherence) is 40% or 0.40, we have:

V = 1 \times 0.40 = 0.40

Therefore, the visibility of the fringes is 40%.

Q10Engineering Physics

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