Home Work #3 - Wave OpticsContact Number: 8527521718Home Work #3 - Wave OpticsContact Number: 8527521718In Young's experiment, light of wavelength \(4000~\mathring{A}\) is used to produce bright fringes of width \(0.6\) mm, at a distance of \(2\) meters. If the whole apparatus is dipped in a liquid of refractive index \(1.5\), then fringe width will be:
1. \(0.2~\text{mm}\)
2. \(0.3~\text{mm}\)
3. \(0.4~\text{mm}\)
4. \(1.2~\text{mm}\)
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. \(2:1\)
In Young’s double slit experiment, the slits are \(2~\text{mm}\) apart and are illuminated by photons of two wavelengths \(\lambda_1 = 12000~\mathring{A}\) and \(\lambda_2 = 10000~\mathring{A}\). At what minimum distance from the common central bright fringe on the screen, \(2~\text{m}\) from the slit, will a bright fringe from one interference pattern coincide with a bright fringe from the other?
1. \(6~\text{mm}\)
2. \(4~\text{mm}\)
3. \(3~\text{mm}\)
4. \(8~\text{mm}\)
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 \(1~\text{mm}.\) The distance between the screen and slits is \(1~\text m.\) The distance between third dark and fifth bright fringe will be:
1. \(3.2~\text{mm}\)
2. \(1.63~\text{mm}\)
3. \(0.585~\text{mm}\)
4. \(2.31~\text{mm}\)
In Young's double-slit experiment using the light of wavelength \(\lambda\), \(60\) fringes are seen on a screen. If the wavelength of light is decreased by \(50\%\), then the number of fringes on the same screen will be:
1. \(30\)
2. \(60\)
3. \(120\)
4. \(90\)
In Young's double-slit experiment, the ratio of maximum intensity at a point to the intensity at the same point when one slit is closed, is:
1. \(2\)
2. \(3\)
3. \(4\)
4. \(1\)
In Young's double-slit experiment sources of equal intensities are used.
The distance between the slits is \(d\) and the wavelength of light used is \(\lambda (\lambda<<d)\). The angular separation of nearest points on either side of central maximum where intensities become half of the maximum value is:
1. \(\frac{\lambda}{d}\)
2. \(\frac{\lambda}{2d}\)
3. \(\frac{\lambda}{4d}\)
4. \(\frac{\lambda}{6d}\)
Young's double-slit experiment is performed in a liquid. The \(10\)th bright fringe in the liquid lies where the \(8\)th dark fringe lies in a vacuum. The refractive index of the liquid
is approximately:
1. \(1.81\)
2. \(1.67\)
3. \(1.54\)
4. \(1.33\)
Two coherent sources are \(0.3~\text{mm}\) apart. They are \(1~\text{m}\) away from the screen. The second dark fringe is at a distance of \(0.3~\text{cm}\) from the center. The distance of the fourth bright fringe from the centre is:
1. \(0.6~\text{cm}\)
2. \(0.8~\text{cm}\)
3. \(1.2~\text{cm}\)
4. \(0.12~\text{cm}\)
In Young's double-slit experiment, an electron beam is used to obtain an interference pattern. If the speed of electrons is increased:
| 1. | No interference pattern will be observed. |
| 2. | Distance between two consecutive fringes remains the same. |
| 3. | Distance between two consecutive fringes will decrease. |
| 4. | Distance between two consecutive fringes will increase. |
In Young's double-slit experiment, the separation \(d\) between the slits is \(2\) mm, the wavelength \(\lambda\) of the light used is \(5896~\mathring{A}\) and distance \(D\) between the screen and slits is \(100\) cm. It is found that the angular width of the fringes is \(0.20^{\circ}\). To increase the fringe angular width to \(0.21^{\circ}\) (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
| 1. | \(0.2~\text{mm}\) | 2. | \(0.1~\text{mm}\) |
| 3. | \(0.5~\text{mm}\) | 4. | \(0.02~\text{mm}\) |
In Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is \(\lambda\) is \(K\), (\(\lambda\) being the wavelength of light used). The intensity at a point where the path difference is \(\frac{\lambda}{4}\) will be:
1. \(K\)
2. \(\frac{K}{4}\)
3. \(\frac{K}{2}\)
4. zero
In Young’s double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance \(D\) must be changed to,
1. \(2~\text{D}\)
2. \(\frac{\text{D}}{2}\)
3. \(\sqrt{2}~\text{D}\)
4. \(\frac{\text{D}}{\sqrt{2}}\)
The relation between the fringe width for the red light and yellow light is:
(all other things being the same.)
1. \(\beta_\text{red} < \beta_\text{yellow}\)
2. \(\beta_\text{red} > \beta_\text{yellow}\)
3. \(\beta_\text{red} = \beta_\text{yellow}\)
4. \(\beta_\text{red} =2 \beta_\text{yellow}\)
Fringe width in a particular Young's double-slit experiment is measured to be \(\beta.\) What will be the fringe width if the wavelength of the light is doubled, the separation between the slits is halved and the separation between the screen and slits is tripled?
1. \(10\) times
2. \(11\) times
3. Same
4. \(12\) times