In Young's double-slit experiment (slit distance d) monochromatic light of wavelength $\mathrm{\lambda }$ is used and the figure pattern observed at a distance L from the slits. The angular position of the bright fringes are

1. ${\sin }^{-1}\left(\frac{\mathrm{N\lambda }}{\mathrm{d}}\right)$

2. ${\sin }^{-1}\left(\frac{\left(\mathrm{N} + {\displaystyle \frac{1}{2}}\right)\mathrm{\lambda }}{\mathrm{d}}\right)$

3. ${\sin }^{-1}\left(\frac{\mathrm{N\lambda }}{\mathrm{L}}\right)$

4. ${\sin }^{-1}\left(\frac{\left(\mathrm{N} + \frac{1}{2}\right)\mathrm{\lambda }}{\mathrm{L}}\right)$

If the separation between screen and source is increased by 2% what would be the effect on the intensity?

(1) Increases by 4%

(2) Increases by 2%

(3) Decreases by 2%

(4) Decreases by 4%

In Young's double-slit experiment, a point P on the central bright fringe is such that the intensity the point P is 1/4 time the maximum intensity. The distance between the slits is d and the wavelength is $\mathrm{\lambda }$. Then angular separation of point P is

1. ${\sin }^{-1}\left(\frac{\mathrm{\lambda }}{\mathrm{d}}\right)$

2. ${\sin }^{-1}\left(\frac{\mathrm{\lambda }}{2\mathrm{d}}\right)$

3. ${\sin }^{-1}\left(\frac{\mathrm{\lambda }}{3\mathrm{d}}\right)$

4. ${\sin }^{-1}\left(\frac{\mathrm{\lambda }}{4\mathrm{d}}\right)$

In the ideal double-slit experiment when a glass-plate (refractive index 1.5) of thickness t is introduced in the path of one of the interfering beams (wavelength $\mathrm{\lambda }$), the intensity at the position where the central maximum occurred previously remains unchanged. The minimum thickness of the glass-plate is

1. 2$\mathrm{\lambda }$

2. 2$\mathrm{\lambda }$/3

3. $\mathrm{\lambda }$/3

4. $\lambda$

When the angle of incidence on a material is 60°, the reflected light is completely polarized. The velocity of the refracted ray inside the material is (in ms^–1)

1. 3 × 10⁸

2. $\left(\frac{{\displaystyle 3}}{{\displaystyle \sqrt{2}}}\right)\times {10}^8$

3. $\sqrt{3}\times {10}^8$

4. 0.5 × 10⁸

When an unpolarized light of intensity I₀ is incident on a polarizing sheet, the intensity of the light which does not get transmitted is:
1. Zero
2. \(I_0\)
3. \(\dfrac{I_0}{2}\)
4. \(\dfrac{I_0}{4}\)

A parallel beam of monochromatic light of wavelength \(5000~\mathring{A}\) is incident normally on a single narrow slit of width \(0.001\) mm. The light is focused by a convex lens on a screen placed on the focal plane. The first minimum will be formed for the angle of diffraction equal to:
1. \(0^{\circ}\)
2. \(15^{\circ}\)
3. \(30^{\circ}\)
4. \(60^{\circ}\)

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is 

(1) 1.2 mm

(2) 1.2 cm

(3) 2.4 cm

(4) 2.4 mm

What will be the angular width of central maxima in Fraunhoffer diffraction when light of wavelength \(6000~\mathring{A}\) is used and slit width is \(12\times 10^{-5}\) cm:
1. \(2~\text{rad}\)
2. \(3~\text{rad}\)
3. \(1~\text{rad}\)
4. \(8~\text{rad}\)

In Young’s double-slit experiment the fringe width is β. If entire arrangement is placed in a liquid of refractive index n, the fringe width becomes 

(1) $\frac{\beta }{n+1}$

(2) nβ

(3) $\frac{\beta }{n}$

(4) $\frac{\beta }{n-1}$