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:

Two polaroids are in the path of an unpolarized beam of intensity ${\mathrm{I}}_0$ such that no light is emitted from the second polaroid. If a third polaroid, whose polarization axis makes an angle $\mathrm{\theta }$ with the polarization axis of the first polaroid, is placed between these polaroids, then the intensity of light emerging from the last polaroid will be:

1. \(\left ( \frac{I_{0}}{8} \right )\sin^{2}2\theta \)
2. \(\left ( \frac{I_{0}}{4} \right )\sin^{2}2\theta \)
3. \(\left ( \frac{I_{0}}{2} \right )\sin^{4}2\theta \)
4. \(I_{0}\sin^{2}2\theta \)

Red light is generally used to observe diffraction patterns from a single slit. If the blue light is used instead of red light, then the diffraction pattern:

What will be the angular width of central maxima in Fraunhofer diffraction when the light of wavelength \(6000~\mathring A\) is used and slit width is $12\times {10}^{-5}\mathrm{cm}$?

1. 2 rad

2. 3 rad

3. 1 rad

4. 8 rad

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