Find the ratio of intensities of two points P and Q on a screen in a Young's double slit experiment - Physics - Wave Optics

Question

Find the ratio of intensities of two points P and Q on a screen in
a Young's double slit experiment when waves from sources
S1 and S2 have phase difference of (i) π
3 and (ii) π 2 respectively

Ujjval Chauhan · Accepted Answer

Dear student

The resultant intensity of the superposition of two waves of
intensity I1 and I2 is given by
I=I1+I2+2I1I2cosϕwhere ϕ is the phase difference between the waves
 Since in young's doubleslit experiment the light waves coming from one source so the intensity will besame i
e
 I1=I2=Ioso I=2Io+2IocosϕI=2Io1+cosϕso for ϕ=π3IP=2Io1+cosπ3IP=3Ioand  for ϕ=π2IQ=2Io1+cosπ2IQ=2Ioso IPIQ=3Io2Io=1
5

Find the ratio of intensities of two points P and Q on a screen in a Young's double slit experiment when waves from sources S1 and S2 have phase difference of (i) π 3 and (ii) π 2 respectively.

Find the ratio of intensities of two points P and Q on a screen in a Young's double slit experiment when waves from sources S₁ and S₂ have phase difference of (i) $\frac{π}{3}$ and (ii) $\frac{π}{2}$ respectively.