The Brewster's angle for an interface should be:
1. \(30^{\circ}<i_b<45^{\circ}\)
2. \(45^{\circ}<i_b<90^{\circ}\)
3. \(i_b=90^{\circ}\)
4. \(0^{\circ}<i_b<30^{\circ}\)
In Young's double-slit experiment, if the separation between coherent sources is halved and the distance of the screen from the coherent sources is doubled, then the fringe width becomes:
1. | half | 2. | four times |
3. | one-fourth | 4. | double |
Two coherent sources of light interfere and produce fringe patterns on a screen. For the central maximum, the phase difference between the two waves will be:
1. zero
2. \(\pi\)
3. \(\frac{3\pi}{2}\)
4. \(\frac{\pi}{2}\)
The angular width of the central maximum in the Fraunhofer diffraction for \(\lambda=6000~\mathrm{\mathring{A}}\) is \(\theta_0\). When the same slit is illuminated by another monochromatic light, the angular width decreases by \(30\%\). The wavelength of this light is:
1. \(1800~\mathrm{\mathring{A}}\)
2. \(4200~\mathrm{\mathring{A}}\)
3. \(420~\mathrm{\mathring{A}}\)
4. \(6000~\mathrm{\mathring{A}}\)
In Young's double-slit experiment, if there is no initial phase difference between the light from the two slits, a point on the screen corresponding to the fifth minimum has a path difference:
1. \(
\frac{5\lambda}{2}
\)
2. \(
\frac{10\lambda}{2}
\)
3. \(
\frac{9\lambda}{2}
\)
4. \(
\frac{11\lambda}{2}
\)
For a crystal with λ = 1 Å and Bragg's angle θ = 60°, the second-order diffraction, 'd' (distance between two consecutive atomic layers) will be:
1. 1.15 Å
2. 0.75 Å
3. 0.55 Å
4. 2.1 Å
The interplanar distance in a crystal is \(2.8 \times 10^{-8} \) m. The value of the maximum wavelength which can be diffracted:
1. \(2.8 \times 10^{-8} \)
2. \(5.6 \times 10^{-8} \)
3. \(1.4 \times 10^{-8} \)
4. \(7.6 \times 10^{-8} \)
In a double-slit experiment, when the light of wavelength \(400~\text{nm}\) was used, the angular width of the first minima formed on a screen placed \(1~\text{m}\) away, was found to be \(0.2^{\circ}\). What will be the angular width of the first minima, if the entire experimental apparatus is immersed in water? \(\left(\mu_{\text{water}} = \frac{4}{3}\right)\)
1. \(0.1^{\circ}\)
2. \(0.266^{\circ}\)
3. \(0.15^{\circ}\)
4. \(0.05^{\circ}\)
Two periodic waves of intensities I1 and I2 pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is:
1.
2.
3.
4.
1. | The angular width of the central maximum of the diffraction pattern will increase. |
2. | The angular width of the central maximum will decrease. |
3. | The angular width of the central maximum will be unaffected. |
4. | A diffraction pattern is not observed on the screen in the case of electrons. |