Assertion (A): Light is diffracted around the edges of obstacles and it bend such a way which is not easily observed.
Reason (R): The wavelength of light is very small.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Diffraction is noticeable when the wavelength is comparable to the obstacle size. Light has a very small wavelength \( approx 400-700 \text{ nm}\), making its diffraction around macroscopic objects hard to observe. Hence, both A and R are true, and R is the correct explanation for A.
Assertion (A): Diffraction is common in sound but not common in light waves.
Reason (R): Wavelength of light wave is more than the wavelength of sound.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Diffraction is pronounced when the wavelength is comparable to the obstacle size. Sound waves have large wavelengths (\( \text{meters}\)), making their diffraction common around everyday objects. Light waves have very small wavelengths (\( \text{nanometers}\)), so their diffraction is less observed. Thus, A is true. The wavelength of light is significantly smaller than the wavelength of sound. Thus, R is false.
Assertion (A): In everyday life, we do not encounter diffraction of light in contrast to that for sound.
Reason (R): Diffraction characteristic is not exhibited by all kind of waves.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Assertion (A) is true: Observable diffraction occurs when wavelength is comparable to obstacle size. Light's wavelength is very small (nanometers), so its diffraction is not easily observed in daily life, unlike sound (wavelength in meters).
Reason (R) is false: Diffraction is a fundamental property of all waves, although its prominence depends on the wavelength and obstacle size. Hence, (A) is true, (R) is false.
Assertion (A): We cannot get diffraction pattern from a wide slit illuminated by monochromatic light.
Reason (R): In diffraction pattern, all the bright bands are not of the same intensity.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
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Assertion (A) is true in a practical sense; a very wide slit (\(a \gg lambda\)) yields a pattern with very small angular spread, making it indiscernible. Reason (R) is true; the intensity of secondary maxima decreases rapidly. (R) does not explain (A).
Assertion (A): Diffraction of light is due to dispersion.
Reason (R): Change in path of light around “the corners separates the wavelength of various colours.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Assertion (A) is false; diffraction is the bending of waves, while dispersion is wavelength-dependent refractive index. Reason (R) is false; color separation in diffraction is due to \(\theta \propto \lambda\), not dispersion around corners.
Assertion (A): Diffraction is a sure indication of wave nature.
Reason (R): Only transverse waves can be diffracted.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Diffraction, the bending of waves around obstacles, is a hallmark of wave phenomena, so (A) is true. However, both transverse waves (like light) and longitudinal waves (like sound) can be diffracted, making (R) false.
Assertion (A): We cannot get diffraction pattern from a wide slit illuminated by monochromatic light.
Reason (R): In diffraction pattern, all the bright bands are not of the same intensity.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
A diffraction pattern always exists, but for a very wide slit compared to wavelength, it's very narrow and practically unobservable, making (A) practically true. In single-slit diffraction, the central maximum is brightest, and other maxima are less intense, so (R) is true. (R) does not explain (A).
Assertion (A): Diffraction of light is due to dispersion.
Reason (R): Change in path of light around “the corners separates the wavelength of various colours.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Diffraction is the bending of waves around obstacles or through apertures. Dispersion is the phenomenon where a wave's phase velocity depends on its frequency, leading to color separation. These are distinct phenomena. Both assertion and reason are false.