MCQ
Two sources are called coherent if they produce waves:
- AOf equal wavelength.
- BOf equal velocity.
- CHaving same shape of wavefront.
- DHaving a constant phase difference.
✓
Answer
- Having a constant phase difference.
Explanation:
For light waves emitted by two sources of light to remain coherent, the initial phase difference between waves should remain constant in time. If the phase difference changes continuously or randomly with time, then the sources are incoherent.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The maximum intensity of fringes in Young's experiment is I. If one of the slit is closed, then the intensity at that place becomes Io. Which of the following relation is true ?
|
(a) I = Io |
(b) I = 2Io |
|
(c) I = 4Io |
(d) There is no relation between I and Io |
The maximum intensity in Young's double slit experiment is I0. Distance between the slits is d = 5 l, where l is the wavelength of monochromatic light used in the experiment. What will be the intensity of light in front of one of the slits on a screen at a distance D = 10d
|
(a) |
(b) |
(c) |
(d) |
Cathode rays are similar to visible light rays in that
|
(a) They both can be deflected by electric and magnetic fields |
|
(b) They both have a definite magnitude of wavelength |
|
(b) They both have a definite magnitude of wavelength |
|
(d) They both can expose a photographic plate |
An electric current i enters and leaves a uniform circular wire of radius a through diametrically opposite points. A charged particle q moving along the axis of the circular wire passes through its centre at speed v. The magnetic force acting on the particle when it passes through the centre has a magnitude:
→- $\text{qv}\frac{\mu_0\text{i}}{2\text{a}}$
- $\text{qv}\frac{\mu_0\text{i}}{2\pi\text{a}}$
- $\text{qv}\frac{\mu_0\text{i}}{\text{a}}$
- $\text{Zero}$
A beam of light of wavelength λ and with illumination L falls on a clean surface of sodium. If N photoelectrons are emitted each with kinetic energy E, then
|
(a) N ∝ L and E ∝ L |
(b) N ∝ L and E ∝ |
|
(c) N ∝ |
(d) N ∝ |
In a full wave rectifiers, input ac current has a frequency ‘n’. The output frequency of current is
|
(a) n/2 |
(b) n |
(c) 2n |
(d) None of these |
Moment of inertia of a magnetic needle is 40 gm-cm2 has time period 3 seconds in earth's horizontal field = 3.6 
weber/m2. Its magnetic moment will be
(a) 0.5 
|
(b) 5
|
(c) 0.250
|
(d) 5 
|
Consider the following statements regarding series grouping of capacitors and select the correct statements.
- Charge on each capacitor remains same and equals to the main charge supplied by the battery.
- Potential difference and energy distributes in the reverse ratio of capacitance.
- Effective capacitance is even less than the least of teh individual capacitances.
The electric field intensity produced by the radiations coming from 100W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50W bulb at the same distance is:
Which of the following relation is correct in magnetism
|
(a) |
(b) I = V + H |
(c) |
(d) |
