Assertion (A): Wave nature can be proved by phenomena of interference and diffraction.
Reason (R): Only transverse wave can show the phenomena of polarization.
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. Interference and diffraction are characteristic wave phenomena, providing strong evidence for the wave nature of light.
Reason (R) is true. Polarization is a property exclusive to transverse waves, where oscillations are perpendicular to the propagation direction.
Reason (R) describes a unique property of transverse waves, which is distinct from demonstrating wave nature via interference/diffraction. Thus, (R) does not explain (A).
Assertion (A): In a Young’s double slit experiment if slit separation is slightly greater than (nl) if (n) is integer No. of maxima on screen is (2n + 1) & no of minima is (2n).
Reason (R): In Young’s double slit experiment path difference at different position are different.
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. If slit separation (d) is slightly greater than (nlambda), there will be (2n+1) maxima and (2n) minima. Reason (R) is also true as path difference (Delta x = d sintheta) varies with position. However, (R) does not explain the specific count of fringes in (A).
Assertion (A): In standard YDSE experiment if upper slit is slightly moved downward then central maxima shifts downward.
Reason (R): Fringe width in such case will increase.
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; moving a slit shifts the central maxima in the direction of the movement. Reason (R) is false. Fringe width \(\beta = \frac{\lambda D}{d}\) depends on wavelength, screen distance, and slit separation, none of which change.
Assertion (A): If the phase difference between the light waves emerging from the slits of the Young’s experiment is \(\pi\) radian, then central fringe will be dark.
Reason (R): Phase difference is equal to \(\frac{2\pi}{\lambda}\) times the effective path difference.
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. An initial \(\pi\) phase difference means destructive interference at the central point (where path difference is zero). Reason (R) is also true, as \(\Delta\phi = \frac{2\pi}{\lambda} \Delta x). (R) explains how phase difference relates to path difference, justifying (A).
Assertion (A): In YDSE central maxima means the maxima formed with zero optical path difference. It may be formed anywhere on the screen.
Reason (R): In an interference pattern, whatever energy disappears at the minimum, appears at the maximum.
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
Both Assertion (A) and Reason (R) are true statements. Central maxima is indeed defined by zero path difference, and its location can be shifted. Interference redistributes energy, meaning energy is conserved. However, (R) does not explain the definition or position of central maxima in (A).
Assertion (A): Diffraction takes place for all types of waves mechanical or non-mechanical, transverse or longitudinal.
Reason (R): Diffraction’s effects are perceptible only if wavelength of wave is comparable to dimensions of diffracting device.
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
Both Assertion (A) and Reason (R) are true. Diffraction is a universal wave phenomenon, occurring for all wave types. Its effects are most noticeable when the wavelength is comparable to the obstacle's size.
However, (R) states the condition for observation, not the fundamental reason why diffraction occurs for all waves (A).
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): In Young’s double slit experiment if intensity of each source is \(I_0\) then minimum and maximum intensity is zero and \(4I_0\) respectively.
Reason (R): In Young’s double slit experiment energy conservation is not followed.
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
In YDSE with coherent sources of intensity (I_0) each, \(I_{\text{min}} = (\sqrt{I_0} - \sqrt{I_0})^2 = 0\) and \(I_{\text{max}} = (\sqrt{I_0} + \sqrt{I_0})^2 = 4I_0\). Thus, A is true. Energy is conserved in interference; it's redistributed, not destroyed. Thus, R is false.
Assertion (A): Radio waves cannot be diffracted by the buildings.
Reason (R): The wavelength of radio waves 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
Radio waves have wavelengths comparable to or larger than buildings \( \text{meters to kilometers}\), enabling them to diffract easily around obstacles. Thus, A is false. The wavelength of radio waves is large, not small. Thus, R is false.
Assertion (A): In standard YDSE set up with visible light, the position on screen where phase difference is zero appears bright.
Reason (R): In YDSE set up amplitude of electromagnetic field at central bright fringe is not varying with time.
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 zero phase difference signifies constructive interference, resulting in a bright fringe. Hence, A is true. The amplitude of the electromagnetic field at the central bright fringe remains constant over time in a stable interference pattern, but this is not the reason for it being bright due to zero phase difference. Hence, R is true but not the correct explanation for A.