The plane wavefront is incident on a spherical mirror as shown. The reflected wavefront will be:

 

1.		2.
3.		4.

If we observe the single slit Fraunhofer diffraction with wavelength $\mathrm{\lambda }$ and slit width d, the width of the central maxima is 2$\mathrm{\theta }$. On decreasing the slit width for the same wavelength $\mathrm{\lambda }$:

Two polaroids P₁ and P₂ are placed with their axis perpendicular to each other. Unpolarised light of intensity I_o is incident on P₁. A third polaroid P₃ is kept in between P₁ and P₂ such that its axis makes an angle 45° with that of P₁. The intensity of transmitted light through P₂ is:

1. $\frac{I_0}{4}$

2. $\frac{I_0}{8}$

3. $\frac{I_0}{16}$

4. $\frac{I_0}{2}$

A linear aperture whose width is 0.02 cm is placed immediately in front of a lens of focal length 60 cm. The aperture is illuminated normally by a parallel beam of wavelength 5 x 10^-5 cm. The distance of the first dark band of the diffraction pattern from the center of the screen is:

1.  0.10 cm

2.  0.25 cm

3.  0.20 cm

4.  0.15 cm

In Young's double-slit experiment, the separation d between the slits is 2 mm, the wavelength $\lambda$ of the light used is 5896 Å and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is 0.20°. To increase the fringe angular width to 0.21° (with same $\lambda$ and D) the separation between the slits needs to be changed to:

1. 1.8 mm

2. 1.9 mm

3. 2.1 mm

4. 1.7 mm

The intensity at the maximum in a Young's double-slit experiment is I₀. Distance between two slits is d = 5$\lambda$, where $\lambda$ is the wavelength of light used in the experiment. What will be the intensity in front of one of the slits on the screen placed at a distance D = 10d?

1. $\frac{I_0}{4}$

2. $\frac{3}{4}{I}_0$

3. $\frac{I_0}{2}$

4. $I_0$

At the first minimum adjacent to the central maximum of a single slit diffraction pattern, the phase difference between the Huygen’s wavelet from the edge of the slit and the wavelet from the midpoint of the slit is:

1. \(\frac{\pi}{4}~radian\)

2. \(\frac{\pi}{2}~radian\)

3. \(\pi~radian\)

4. \(\frac{\pi}{8}~radian\)$$

In a double-slit experiment, the two slits are 1 mm apart and the screen is placed 1 m away. Monochromatic light of wavelength 500 nm is used. What will be the width of each slit for obtaining ten maxima of double-slit within the central maxima of a single-slit pattern?

1. 0.2 mm

2. 0.1 mm

3. 0.5 mm

4. 0.02 mm

In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is λ is K, (λ being the wavelength of light used). The intensity at a point where the path difference is λ/4 will be:

1. K

2. K/4

3. K/2

4. Zero

The main difference between the phenomena of interference and diffraction is that: