YDSE Problems I

Q. In young's double slit experiment the fringe width with light of wave length 6000 A is found to be 4.0mm. What will be the fringe width if light of wavelength 4800 A is used?

1. 2.8mm
2. 3.2mm
3. 4.0mm
4. 4.8mm

Q. In the Young's double slit experiment shown in the figure, the medium between slit plane and the screen has refractive index varying with time as $n=n_0+kt$, then

1. The y co-ordinates of central maximum is $\frac{D\sin \varphi }{n_0+kt}$.
2. Velocity of central maximum as a function of time is $\frac{-kD\cos \varphi }{(n_0+kt{)}^2}$.
3. If a glass plate of small thickness $p$ is placed in front of $S_1$, then to form central maximum at O, refractive index of glass should vary as $n_0+kt+\frac{d\sin \varphi }{p}$.
4. If a glass plate of small thickness $p$ is placed in front of $S_1$, then to form central maxima at O, refractive index of glass should vary as $n_0+kt+\frac{d\cos \varphi }{p}$

Q.

In an interference arrangement similar to Young's double slit experiment, the slits S₁ and S₂ are illuminated with coherent microwave sources each of frequency 10⁶ Hz. The sources are synchronized to have zero phase difference. The slits are separated by distance d = 150 m. The intensity I(θ)is measured as a function of q, where q is defined as shown. If I₀ is maximum intensity, then I(θ) for 0≤θ≤90° is given by

1. 

2. 

3. 

4.