Coherent sources are those sources for which
|
(a) Phase difference remain constant |
|
(b) Frequency remains constant |
|
(c) Both phase difference and frequency remains constant |
|
(d) None of these |
(c) Both phase difference and frequency remains constant
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A vertical straight conductor carries a current vertically upwards. A point P lies to the east of it at a small distance and another point Q lies to the west at the same distance. The magnetic field at P is
| (a) Greater than at Q |
| (b) Same as at Q |
| (c) Less than at Q |
| (d) Greater or less than at Q depending upon the strength of the current |
Select the correct alternative, The angle between the normal and refracted ray is called:
A convex lens has 9 cm focal length and a concave lens has – 18 cm focal length. The focal length of the combination in contact will be
|
(a) 9 cm |
(b) – 18 cm |
(c) – 9 cm |
(d) 18 cm |
A long solenoid has a radius a and number of turns per unit length is n. If it carries a current i, then the magnetic field on its axis is directly proportional to
|
(a) ani |
(b) ni |
(c) |
(d) |
The potential difference between the cathode and the target in a Collidge tube is 100 kV. The minimum wavelength of the X-rays emitted by the tube is
|
(a) 0.66 Å |
(b) 9.38 Å |
(c) 0.246 Å |
(d) 0.123 Å |
A non-conducting solid sphere of radius R is uniformly charged. The magnitude of the electric field due to the sphere at a distance r from its centre
|
(a) Increases as r increases for r < R |
(b) Decreases as r increases for 0 < r < ∞ |
|
(c) Decreases as r increases for R < r < ∞ |
(d) a, c |
The figure shows a network of currents. The magnitude of currents is shown here. The current i will be
|
(a) 3 A |
(b) 13 A |
(c) 23 A |
(d) – 3 A |
