Advertisements
Advertisements
Question
Which of the following sources provides the best monochromatic light?
Options
A candle
A bulb
A mercury tube
A laser
Solution
A laser
Among the given sources, laser is the best coherent source providing monochromatic light with constant phase difference.
APPEARS IN
RELATED QUESTIONS
Monochromatic light of frequency 6.0 × 1014 Hz is produced by a laser. The power emitted is 2.0 × 10−3 W. Estimate the number of photons emitted per second on an average by the source
'Two independent monochromatic sources of light cannot produce a sustained interference pattern'. Give reason.
When light travels from a rarer to a denser medium, the speed decreases. Does this decrease in speed imply a reduction in the energy carried by the wave?
In the wave picture of light, the intensity of light is determined by the square of the amplitude of the wave. What determines the intensity in the photon picture of light?
A monochromatic ray of light falls on a regular prism. What is the relation between the angle of incidence and angle of emergence in the case of minimum deviation?
State the essential conditions for diffraction of light ?
Monochromatic light of frequency 5.0 × 1014 Hz is produced by a laser. The power emitted is 3.0 × 10–3 W. Estimate the number of photons emitted per second on an average by the source ?
When monochromatic light travels from a rarer to a denser medium, explain the following, giving reasons:
(i) Is the frequency of reflected and refracted light same as the frequency of incident light?
(ii) Does the decrease in speed imply a reduction in the energy carried by light wave?
State Huygen’s principle. Using this principle explain how a diffraction pattern is obtained on a screen due to a narrow slit on which a narrow beam coming from a `=> n = (vlamda)/(vlamda_omega)`monochromatic source of light is incident normally.
If a monochromatic source of light is replaced by white light, what change would you observe in the diffraction pattern?
State with reason, how the linear width of the central maximum will be affected if
(i) monochromatic yellow light is replaced with red light, and
(ii) distance between the slit and the screen is increased.
Monochromatic light of wavelength 650 nm falls normally on a slit of width 1.3 x 10-4 cm and the resulting Fraunhofer diffraction is obtained on a screen. Find the angular width of the . central maxima.
Find the angle of incidence at which a ray of monochromatic light should be incident on the first surface AB of a regular glass prism ABC so that the emergent ray grazes the adjacent surface AC. (Refractive Index of glass = 1 .56)
Monochromatic fight of wavelength 198 nm is incident on the surface of a metallic cathode whose work function is 2.5 eV How much potential difference must be applied between the cathode and the anode of a photocell to just stop the photocurrent from flowing?
(a) Can the interference pattern be produced by two independent monochromatic sources of light? Explain.
(b) The intensity at the central maximum (O) in Young's double-slit experimental set-up shown in the figure is IO. If the distance OP equals one-third of the fringe width of the pattern, show that the intensity at point P, would `"I"_°/4`
(c) In Young's double-slit experiment, the slits are separated by 0⋅5 mm and the screen is placed 1⋅0 m away from the slit. It is found that the 5th bright fringe is at a distance of 4⋅13 mm from the 2nd dark fringe. Find the wavelength of light used.
Using the monochromatic light of the wavelength in the experimental set-up of the diffraction pattern as well as in the interference pattern where the slit separation is 1 mm, 10 interference fringes are found to be within the central maximum of the diffraction pattern. Determine the width of the single slit, if the screen is kept at the same distance from the slit in the two cases.
Assertion(A): The photoelectrons produced by a monochromatic light beam incident on a metal surface have a spread in their kinetic energies.
Reason(R): The energy of electrons emitted from inside the metal surface, is lost in collision with the other atoms in the metal.
A narrow slit is illuminated by a parallel beam of monochromatic light of wavelength λ equal to 6000 Å and the angular width of the central maximum in the resulting diffraction pattern is measured. When the slit is next illuminated by light of wavelength λ’, the angular width decreases by 30%. Calculate the value of the wavelength λ’.
A ray of monochromatic light propagating in the air is incident on the surface of the water. Which of the following will be the same for the reflected and refracted rays?
