Question

A thin film of CCI4 having refractive index 2.46 and thickness 0.1068 μm is spread on water having refractive index 2.33. If viewed at 45° which color will be seen enhanced​

Answer 1

Answer:

4800°A

Explanation:

Condition for observing bright fringe is

2nd=(m+12)λ

∴λ=2nd(m+12)=2×1.5×4×10−5m+12

=12×10−5m+12

The integer m that gives the wavelength in the visible region (4000Å to 7000Å) is m=2. In that case,

λ=12×10−5212=4.8×10−5=4800Å

Answer 2

Answer:

The colour blue of wavelength 4800Å will be seen enhanced.

Explanation:

According to question a 0.1068 μm layer of carbon tetrachloride is spread on the water. And when viewed at a 45° angle some colour is enhanced.

So for us to see light, constructive interference must occur.

• The required condition for observing a bright fringe is 2nd=(m+12)λ which would mean that a constructive interference has occurred.

λ=2nd(m+12)=2×1.5×4×10^-5(m+12)=12×10^-5(m+12)

• The integer m that gives the wavelength in the visible region (4000Å to 7000Å) is m=2.

In that case,

X=12×10^-5(2+12)=4.8×10^-5=4800Å

A light of wawelength 4800Å would be between blue and cyan in colour.

So the colour blue will be seen as enhanced if viewed at a 45° angle.

Project code #SPJ2