Verified Solution • 2025–26 Session moderate

QJEEM21Ph65f0: JEE Main 2021 Physics - Class 12 JEEM21Ph65f0 Solution: The difference in the number of waves when yellow light…

The difference in the number of waves when yellow light propagates through air and vacuum columns of the same thickness is one. The thickness of the air column is ___________ mm. [Refractive index of air = 1.0003, wavelength of yellow light in vacuum = 6000 Ao\mathop A\limits^o ]

Step-by-Step Verified Solution

Thickness t = n λ\lambda

So, n λ\lambda vac = (n + 1) λ\lambda air

n λ\lambda = (n + 1) λμair{\lambda \over {{\mu _{air}}}}

n = 1μair−1=1043{1 \over {{\mu _{air}} - 1}} = {{{{10}^4}} \over 3}

t = n λ\lambda

=1043×6000Ao= {{{{10}^4}} \over 3} \times 6000\mathop A\limits^o

= 2 mm

Related Learning Resources & Exam Preparation

JEE Main PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring