- 1(current)
Q. No.1. \(2\times 10^{-3}\) rad
2. \(2.5\times 10^{-3} \) rad
3. \(3\times 10^{-3}\) rad
4. \(4\times 10^{-3}\) rad
1. \(1.1\times10^{-6}~\text{m}\)
2. \(1.2\times10^{-6}~\text{m}\)
3. \(1.3\times10^{-6}~\text{m}\)
4. \(1.4\times10^{-6}~\text{m}\)
For a parallel beam of monochromatic light of wavelength \(\lambda\), diffraction is produced by a single slit whose width \(a\) is much greater than the wavelength of the light. If \(D\) is the distance of the screen from the slit, the width of the central maxima will be:
| 1. | \(\dfrac{2D\lambda}{a}\) | 2. | \(\dfrac{D\lambda}{a}\) |
| 3. | \(\dfrac{Da}{\lambda}\) | 4. | \(\dfrac{2Da}{\lambda}\) |
1. \({\lambda\over a}\)
2. \({2\lambda\over a}\)
3. \({3\lambda\over 2a}\)
4. \({3\lambda\over a}\)
A diffraction pattern is obtained by using a beam of red light. What will happen, if the red light is replaced by blue light?
1. Bands will become narrower
2. Bands become broader
3. No change will take place
4. Bands disappear
| 1. | \({5}\times{10}^{{-}{5}}~\text{cm}\) | 2. | \({1}{.}{0}\times{10}^{{-}{4}}~\text{cm}\) |
| 3. | \({2}{.}{5}\times{10}^{{-}{5}}~\text{cm}\) | 4. | \({1}{.}{25}\times{10}^{{-}{5}}~\text{cm}\) |
The angular width of the central maximum in the Fraunhofer diffraction for \(\lambda=6000~{\mathring{A}}\) 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. \(1800~{\mathring{A}}\)
2. \(4200~{\mathring{A}}\)
3. \(420~{\mathring{A}}\)
4. \(6000~{\mathring{A}}\)
A single slit of width \(0.1~\text{mm}\) is illuminated by a parallel beam of light of wavelength \(6000~\mathring A.\) The diffraction pattern is observed on a screen placed \(0.5~\text{m}\) away from the slit. What is the distance of the third dark fringe from the central bright fringe?
| 1. | \(3~\text{mm}\) | 2. | \(1.5~\text{mm}\) |
| 3. | \(9~\text{mm}\) | 4. | \(4.5~\text{mm}\) |
1. \(1.2\) \(\mu \text{m}\)
2. \(1.5\) \(\mu \text{m}\)
3. \(1.0\) \(\mu \text{m}\)
4. \(1.8\) \(\mu \text{m}\)
- 1(current)
Q. No.
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