MCQ
Coherent sources are those sources for which
  • A
    Phase difference remain constant
  • B
    Frequency remains constant
  • Both phase difference and frequency remains constant
  • D
    None of these

Answer

Correct option: C.
Both phase difference and frequency remains constant
c
A coherent source continuously emits light with a constant frequency and wavelength. Also, the phase difference in the light waves are always constant. If these properties are satisfied, only then a source is called coherent.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Which of the following transition will have highest emission wavelength
A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is
The effective length of a magnet is $ 31.4 \,cm $ and its pole strength is $0.5\, Am$. The magnetic moment, if it is bent in the form of a semicircle will be.....$A{m^2}$
A ray of light is incident on a thick slab of glass of thickness $t$ as shown in the figure.  The  emergent ray is parallel to the incident ray but displaced sideways by a distance $d$. If  the angles are small then $d$ is
An equi$-$convex crown glass lens has a focal length $20 \ cm$ for violet rays. Here $\mu_{ v }=1.5 \ \mu_{ r }=1.47$. Its focal length for red rays is
The value of amplification factor from the following graph will be
Half lives of two radioactive substances A and B are respectively 20 minutes and 40 minutes. Initially the sample of A and B have equal number of nuclei. After 80 minutes, the ratio of remaining number of A and B nuclei is
Diameter of a plano-convex lens is $6\ cm$ and thickness at the centre is $3\  mm$. If speed of light in material of lens is $2 × 10^8\  m/s$, the focal length of the lens is.......$cm$
In order to obtain a time constant of $10$ seconds in an $RC$ circuit containing a resistance of $10^3\,\Omega,$ the capacity of a condenser should be.....$ \mu F$
In the CB mode of a transistor, when the collector voltage is changed by 0.5 volt. The collector current changes by 0.05 mA. The output resistance will be