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. \(
\frac{11\lambda}{2}
\)
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. \(0.05^{\circ}\)
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 |
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. \(0^{\circ}<i_b<30^{\circ}\)
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. \(\frac{\pi}{2}\)
1. | \(60^\circ\) | 2. | \(75^\circ\) |
3. | \(30^\circ\) | 4. | \(45^\circ\) |
A monochromatic light of frequency \(500\) THz is incident on the slits of a Young's double slit experiment. If the distance between the slits is \(0.2\) mm and the screen is placed at a distance \(1\) m from the slits, the width of \(10\) fringes will be:
1. \(1.5\) mm
2. \(15\) mm
3. \(30\) mm
4. \(3\) mm
1. | \(\frac{I}{2}\) | 2. | \(\frac{I}{3}\) |
3. | \(\frac{3I}{4}\) | 4. | \(\frac{2I}{3}\) |