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. \(60^{\circ}\)
The direction of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by:
\((a\) is the width of the slit)
1. \(a\sin\theta = \frac{\lambda}{2}\)
2. \(a\cos\theta = \frac{3\lambda}{2}\)
3. \(a\sin\theta = \lambda\)
4. \(a\sin\theta = \frac{3\lambda}{2}\)
In two separate set-ups of the Young's double slit experiment, fringes of equal width are observed when lights of wavelengths in the ratio \(1:2\) are used. If the ratio of the slit separation in the two cases is \(2:1\), the ratio of the distances between the plane of the slits and the screen in the two set-ups is:
1. \(4:1\)
2. \(1:1\)
3. \(1:4\)
4. \(2:1\)
Which of the following statements indicates that light waves are transverse?
1. | Light waves can travel in a vacuum. |
2. | Light waves show interference. |
3. | Light waves can be polarized. |
4. | Light waves can be diffracted. |
By Huygen's wave theory of light, we cannot explain the phenomenon of:
1. | Interference |
2. | Diffraction |
3. | Photoelectric effect |
4. | Polarisation |
A diffraction pattern is observed using a beam of red light. What will happen if the red light is replaced by the blue light?
1. | No change takes place. |
2. | Diffraction bands become narrower. |
3. | Diffraction bands become broader. |
4. | Diffraction pattern disappears. |
In Young's double-slit experiment, the slit separation is doubled. This results in:
1. | An increase in fringe intensity |
2. | A decrease in fringe intensity |
3. | Halving of the fringe spacing |
4. | Doubling of the fringe spacing |
In Young's double-slit experiment the light emitted from the source has \(\lambda = 6.5\times 10^{-7}~\text{m}\) and the distance between the two slits is \(1\) mm. The distance between the screen and slits is \(1\) metre. Distance between third dark and fifth bright fringe will be:
1. \(3.2\) mm
2. \(1.63\) mm
3. \(0.585\) mm
4. \(2.31\) mm
Two superposing waves are represented by the following equations:
\(y_1=5 \sin 2 \pi(10{t}-0.1 {x}), {y}_2=10 \sin 2 \pi(10{t}-0.1 {x}).\)
Ratio of intensities \(\frac{I_{max}}{I_{min}}\) will be:
1. \(1\)
2. \(9\)
3. \(4\)
4. \(16\)
Unpolarized light of intensity \(32\) Wm–2 passes through three polarizers such that the transmission axes of the first and second polarizer make an angle of \(30^{\circ}\) with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of the final emerging light will be:
1. \(32\) Wm–2
2. \(3\) Wm–2
3. \(8\) Wm–2
4. \(4\) Wm–2