NEET Physics Question - Wave Optics - Young's Double Slit Experiment

Assertion (A): In YDSE, fringes with blue light are thicker than those for red light.

Reason (R): In YDSE, the \(n^{\text{th}}\) maxima always comes before the \(n^{\text{th}}\) minima.

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

Solution:

Fringe width \(\beta = \frac{\lambda D}{d}\). Since \(\lambda_{\text{blue}} < \lambda_{\text{red}}\), blue fringes are thinner than red fringes, so A is false. Minima and maxima alternate, and the \(n^{\text{th}}\) dark fringe typically occurs closer to the central maximum than the \(n^{\text{th}}\) bright fringe (for (n ge 1)). So R is also false.

Rankers Physics

YDSE Fringe Width and Maxima/Minima Positions

Solution:

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