Physics Circle home Student Login

Home›Chapters›Wave Optics PYQs›YDSE: Fringe Width & Fringe Positions›Question 50

MHT CET 2021 (20 Sep, Shift 1) · YDSE: Fringe Width & Fringe Positions

YDSE: Fringe Width & Fringe Positions question from MHT CET 2021 (20 Sep, Shift 1)

Q50MHT CET 2021 · 20 SEP · SHIFT 1Easy

YDSE: Fringe Width & Fringe Positions

In Young's double slit experiment, the 'nthn^{\text{th}}' maximum of wavelength 'λ1\lambda_1 ' is at a distance 'y1y_1' from the central maximum. When the wavelength of the source is changed to 'λ2\lambda_2', (n2)\left(\frac{n}{2}\right)th maximum is at a distance of 'y2y_2' from its central maximum. The ratio y1y2\frac{y_1}{y_2} is

Show answer and solution

Answer: (b)

  1. Bright fringe: yn=nλDdy_n = \frac{n\lambda D}{d}
  2. y1=nλ1Ddy_1 = \frac{n\lambda_1 D}{d}, y2=(n/2)λ2Ddy_2 = \frac{(n/2)\lambda_2 D}{d}
  3. y1y2=nλ1(n/2)λ2=2λ1λ2\frac{y_1}{y_2} = \frac{n\lambda_1}{(n/2)\lambda_2} = \frac{2\lambda_1}{\lambda_2}
  4. So the answer is (b) 2λ1λ2\frac{2\lambda_1}{\lambda_2}.
Report a mistake

More questions on YDSE: Fringe Width & Fringe Positions