Q. In the Young’s double slit experiment, if the phase difference between the two waves interfering at a point is $\phi$, the intensity at that point can be expressed by the expression
A) $I = \sqrt{A^{2} + B^{2}\cos^{2}\phi}$
B) $I = \frac{A}{B}\cos\phi$
C) $I = A + B\cos\frac{\phi}{2}$
D) $I = A + B\cos\phi$
Explanation
(d) $I = a_{1}^{2} + a_{2}^{2} + 2a_{1}a_{2}\cos\phi$
Put $a_{1}^{2} + a_{2}^{2} = A$ and$\ a_{1}a_{2} = B;\ \therefore I = A + B\cos\phi$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.