BITSAT2024PhysicsWave OpticsActual
In YDSE, monochromatic light falls on a screen 1.80 m from two slits separated by 2.08 mm . The first and second order bright fringes are separated by 0.553 mm . The wavelength of light used is
Options
- A520 nm
- B639 nm
- C715 nm
- DNone of these
Correct answer
B. 639 nm
Step-by-step solution
Position of first bright fringe, y₁= D d Position of second bright fringe, aligned y₂ & = 2 D d y₂-y₁ & = 2 D d - D d y₂-y₁ & = D d or & = (y₂-y₁ ) d D aligned Substituting given values, we have aligned & = 0.553 10⁻³ 2.08 10⁻³ 1.8 & =639 10⁻⁹ ~m or & =639 ~nm aligned