Q. No.Two sources are called coherent if they produce waves:
| 1. | of equal wavelength |
| 2. | of equal velocity |
| 3. | having same shape of wavefront |
| 4. | having a constant phase difference |
Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is \(25.\) The intensities of the sources are in the ratio:
1. \(25:1\)
2. \(5:1\)
3. \(9:4\)
4. \(625:1\)
The slits in a Young's double-slit experiment have equal width and the source is placed symmetrically with respect to the slits. The intensity at the central fringe is \(I_0.\) If one of the slits is closed, the intensity at this point will be:
1. \(I_0\)
2. \(I_0/4\)
3. \(I_0/2\)
4. \(4I_0\)
1. \(4\)
2. \(2\)
3. \(5\)
4. \(2.5\)
1. \(\dfrac{2d^2}{D}\)
2. \(\dfrac{2d^2}{3D}\)
3. \(\dfrac{d^2}{2D}\)
4. \(\dfrac{d^2}{6D}\)
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. angular separation of the fringes increases.
2. angular separation of the fringes decreases.
3. linear separation of the fringes increases.
4. linear separation of the fringes decreases.
Two slits are made one millimetre apart and the screen is placed one meter away. What is the fringe separation when blue-green light of wavelength \(500\) nm is used?
1. \(0.5\) mm
2. \(0.3\) mm
3. \(0.05\) mm
4. \(0.03\) mm
| Statement I: | If screen is moved away from the plane of slits, angular separation of the fringes remains constant. |
| Statement Ii: | If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of fringes decreases. |
| 1. | Statement I is False but Statement II is True. |
| 2. | Both Statement I and Statement II are True. |
| 3. | Both Statement I and Statement II are False. |
| 4. | Statement I is True but Statement II is False. |
Which of the following sources gives the best monochromatic light?
1. a candle
2. a bulb
3. a mercury tube
4. a laser
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