Diffraction (due to a single slit, width of central maximum ) NEET Questions

Physics - Optics

Diffraction (due to a single slit, width of central maximum ) MCQ Questions


1.
Diffraction of light is defined as:
A.
The change in speed of light when it enters a denser medium
B.
The bouncing back of light from a polished surface
C.
The bending or spreading of light waves around the edges of an obstacle or through a narrow aperture, with deviation from rectilinear propagation
D.
The splitting of white light into its constituent colours by a prism
😑 View Answer Rough Work Error
ANSWER :
C. The bending or spreading of light waves around the edges of an obstacle or through a narrow aperture, with deviation from rectilinear propagation
2.
The condition for PRONOUNCED diffraction through a single slit is:
A.
The wavelength must be much larger than the distance to the screen
B.
The slit width must be much larger than the wavelength (a >> λ)
C.
The slit width must be exactly equal to 10λ
D.
The width of the slit (a) must be comparable to or smaller than the wavelength of light (a ≈ λ or a < λ)
😑 View Answer Rough Work Error
ANSWER :
D. The width of the slit (a) must be comparable to or smaller than the wavelength of light (a ≈ λ or a < λ)
3.
Diffraction was first systematically studied by:
A.
Thomas Young (1801) who performed the double-slit interference experiment
B.
Isaac Newton (1666) who observed coloured fringes in thin films
C.
Augustin-Jean Fresnel (1818) who developed the wave theory of diffraction using Huygens' principle with phase considerations
D.
James Clerk Maxwell (1865) who derived the electromagnetic wave equations
😑 View Answer Rough Work Error
ANSWER :
C. Augustin-Jean Fresnel (1818) who developed the wave theory of diffraction using Huygens' principle with phase considerations
4.
The phenomenon of diffraction proves the _____ nature of light.
A.
Electromagnetic nature — diffraction only works for transverse waves
B.
Wave nature — diffraction is a characteristic behaviour of waves that particles cannot exhibit
C.
Dual (wave-particle) nature equally — both waves and particles diffract
D.
Particle nature — photons bend around edges due to gravitational attraction
😑 View Answer Rough Work Error
ANSWER :
B. Wave nature — diffraction is a characteristic behaviour of waves that particles cannot exhibit
5.
In a single-slit diffraction experiment, the slit width is 'a', wavelength is λ, and screen distance is D. The condition for the FIRST DIFFRACTION MINIMUM is:
A.
a sinθ = λ (or for small angles: a × (y₁/D) = λ, where y₁ is the distance of first minimum from centre)
B.
a sinθ = nλ for n = 0, 1, 2...
C.
a sinθ = λ/2
D.
a sinθ = 2λ
😑 View Answer Rough Work Error
ANSWER :
A. a sinθ = λ (or for small angles: a × (y₁/D) = λ, where y₁ is the distance of first minimum from centre)
6.
The condition for the nth SECONDARY MINIMUM in single-slit diffraction is:
A.
a sinθ = nλ/2 for n = 1, 2, 3...
B.
a sinθ = nλ, where n = ±1, ±2, ±3,... (integers; n = 0 is the centre of the central maximum, NOT a minimum)
C.
a sinθ = nλ for n = 0, 1, 2... including n = 0
D.
a sinθ = (2n+1)λ/2 — these are secondary maxima positions
😑 View Answer Rough Work Error
ANSWER :
B. a sinθ = nλ, where n = ±1, ±2, ±3,... (integers; n = 0 is the centre of the central maximum, NOT a minimum)