EASY
Earn 100

Calculate the maximum order of diffraction maxima seen from a plane diffraction grating having 5500 lines per cm if light of wavelength 5896 A falls normally on it.

Important Questions on Wave Optics

EASY
Light travels in a straight line because
EASY

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : An electron microscope can achieve better resolving power than an optical microscope.

Reason R : The de Broglie's wavelength of the electrons emitted from an electron gun is much less than wavelength of visible light.

In the light of the above statements, choose the correct answer from the options given below:

EASY
The speed of electrons in a scanning electron microscope is 1×107 ms-1. If the protons having the same speed are used instead of electrons, then the resolving power of scanning proton microscope will be changed by a factor of:
EASY
Two poles are separated by a distance of 3.14 m The resolving power of human eye is 1minute of an arc. The maximum distance from which he can identify the two poles distinctly is
MEDIUM

A grating with 400 lines per mm is illuminating with the light of wavelength 600.0nm.

b. Determine the largest order that can be seen with which this grating and this wavelength.

EASY

A student is trying to make an accurate measurement of the wavelength of green light from a mercury lamp. The wavelength $\lambda$ of this light is 546 nm. Using a double-slit of separation 0.50 mm, the student can see 10 clear bright fringes on a screen at a distance of 0.80 m from the slits. The student can measure their overall width to within ±1 mm

Using a ruler. The student then tries an alternative experiment using a diffraction grating with 3000 lines cm-1. The angle between the two second-order maxima can be measured to within ±0.1°.

(b) Determine the angle of the second-order maximum that the student can measure in the second experiment.

MEDIUM

White light is incident normally on a diffraction grating with a slit-separation d of 2.00×10-6 m. The visible spectrum has wavelengths between 400 nm and 700 nm.

(a) Calculate the angle between the red and violet ends of the first-order spectrum.

EASY

White light is incident normally on a diffraction grating with a slit-separation d of 2.00×10-6 m. The visible spectrum has wavelengths between 400 nm and 700 nm.

(b) Explain why the second-and third-order spectra overlap.

MEDIUM
A plane transmission grating having 6000 lines per cm is illuminated by white light. Calculate the angular separation between the two lines of wavelengths 5882 A∘ and 5852 A∘ in the first-order spectrum.
MEDIUM

The spectrum of sodium includes two lines at wavelength 588.995 nm and 589.592nm. A sodium lamp is viewed by a diffraction grating that just manages to resolve these two lines in the third order at 12°. Determine

b. The total number of ruling on the grating.

EASY

(b) This diagram shows the experimental setup (left) used to analyse the spectrum of a sodium discharge lamp with a diffraction grating with 500 lines mm-1, and the spectral lines observed (right) in the developed photographic film.

Question Image

(i) Explain why two spectra are observed.

EASY

Consider the equation dsinθ=nλ. State and explain how the interference pattern would change when:

(a) The wavelength of the incident light is increased for the same grating

MEDIUM
A diffraction grating is 5.0mm wide and has 600 lines per mm. A beam of light containing a range of wavelengths is incident on the grating. The average wavelength is 550nm. Determine the least wavelength range that can be resolved in the second order.
EASY

Consider the equation dsinθ=nλ. State and explain how the interference pattern would change when:

(b) The grating is changed for one with more lines per cm for the same incident light.

HARD
Discuss the experiment to determine the wavelength of different colours using diffraction grating.
EASY

(b) This diagram shows the experimental setup (left) used to analyse the spectrum of a sodium discharge lamp with a diffraction grating with 500 lines mm-1, and the spectral lines observed (right) in the developed photographic film.

Question Image

(iii) The green maximum near end A is at an angle θ of 19.5°. Calculate the wavelength of the green light.

EASY

The spectrum of sodium includes two lines at wavelength 588.995 nm and 589.592nm. A sodium lamp is viewed by a diffraction grating that just manages to resolve these two lines in the third-order at 12°. Determine

a. The slit spacing d of the grating.

EASY

(b) This diagram shows the experimental setup (left) used to analyse the spectrum of a sodium discharge lamp with a diffraction grating with 500 lines mm-1, and the spectral lines observed (right) in the developed photographic film.

Question Image

(iv) Calculate the angle produced by the second green line.

EASY

One of the spectral lines from a hydrogen discharge lamp has wavelength 656 nm. This light is incident normally at a diffraction grating with 5000 lines cm-1.

Calculate the angles for the first- and second-order maxima for this light

MEDIUM

A grating with 400 lines per mm is illuminating with the light of wavelength 600.0nm.

a. Determine the angles at which maxima are observed.