Assume that light of wavelength 600 nm is coming from a star. The limit of resolution of telescope whose objective has a diameter of 2 m is:
1.
2.
3.
4.
When the light diverges from a point source, the shape of the wavefront is:
1. Parabolic.
2. Plane.
3. Spherical.
4. Elliptical.
Which of the following is not true?
1. | The speed of light is dependent on the colour of the light. |
2. | The speed of violet light is less than the speed of the red light in glass. |
3. | The frequency of light never depends upon the property of the medium. |
4. | When the light diverges from a point source, the shape of the wavefront is plane. |
What will be the angular width of central maxima in Fraunhofer diffraction when the light of wavelength \(6000~\mathring {A}\) is used and slit width is \(12\times 10^{-5}~\text{cm}\)?
1. \(2~\text{rad}\)
2. \(3~\text{rad}\)
3. \(1~\text{rad}\)
4. \(8~\text{rad}\)
Red light is generally used to observe diffraction patterns from a single slit. If the blue light is used instead of red light, then the diffraction pattern:
1. | will be clearer. |
2. | will contract. |
3. | will expand. |
4. | will not be visible. |
Two polaroids are in the path of an unpolarized beam of intensity \(I_0\) such that no light is emitted from the second polaroid. If a third polaroid, whose polarization axis makes an angle \(\theta\) with the polarization axis of the first polaroid, is placed between these polaroids, then the intensity of light emerging from the last polaroid will be:
1. \(\left ( \frac{I_{0}}{8} \right )\sin^{2}2\theta \)
2. \(\left ( \frac{I_{0}}{4} \right )\sin^{2}2\theta \)
3. \(\left ( \frac{I_{0}}{2} \right )\sin^{4}2\theta \)
4. \(I_{0}\sin^{2}2\theta \)
The main difference between the phenomena of interference and diffraction is that:
1. | diffraction is caused by reflected waves from a source whereas interference is caused due to the refraction of waves from a source. |
2. | diffraction is caused due to the interaction of waves derived from the same source, whereas interference is the bending of light from the same wavefront. |
3. | diffraction is caused due to the interaction of light from the same wavefront, whereas the interference is the interaction of two waves derived from the same source. |
4. | diffraction is caused due to the interaction of light from the same wavefront whereas interference is the interaction of waves from two isolated sources. |
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
1. | \(0.2~\text{mm}\) | 2. | \(0.1~\text{mm}\) |
3. | \(0.5~\text{mm}\) | 4. | \(0.02~\text{mm}\) |