YDSE Central Maxima Shift and Fringe Width – Rankers Physics

Young's Double Slit Experiment: Practice Problem & Solution

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.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Young's Double Slit Experiment. Understanding the underlying formula is key to arriving at the correct answer below:

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.

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Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. Assertion (A): As the separation between the two slits is increased width of fringes decreases. Reason (R): On increasing separation between two slits, angular separation of fringes decreases.  
2. Assertion (A): The central fringe is bright or dark, it depends on the initial phase difference between the two coherent sources. Reason (R): The pattern and position of fringes always remains same even after the introduction of transparent medium in a path of one of the slit.  
3. Assertion (A): Wave nature can be proved by phenomena of interference and diffraction. Reason (R): Only transverse wave can show the phenomena of polarization.
4. Assertion (A): In Young's double slit experiment, if one of the slits is closed, intensity at the position of central fringe becomes half. Reason (R): Resultant intensity, being sum of intensities from individual slits, becomes half as one slit is closed.  
5. Assertion (A): When tiny circular obstacle is placed in the path of light from some distance, a bright spot is seen at the centre of shadow of the obstacle. Reason (R): Constructive interference occurs at the centre of the shadow.