Question

In a biprism experiment the micrometer reading for zero order nd tenth order fringes are 1.25mm nd 2.37mm respectively when light of wavelength 5.90×10^-7 is used.now what will be the position of zero order nd tenth order fringes if wavelength is changed to7.50×10^-7m?​

Answer 1

Answer:0 Newton's rings are observed in reflected light of wavelength 5900 Å. ... In a biprism experiment the micrometer reading for zero order and tenth order fringes are 1.25 mm and 2.37 mm respectively when light of λ = 5.90 ´ 10-5 cm. is used. Now what will be the position of zero order and tenth order if λ is ...

Step-by-step explanation:

Answer 2

Given:

The reading for the zero-order fringe= 1.25 mm

The reading for tenth order fringe = 2.37 mm

The wavelength of the light used = 5.90 X 10⁻⁷m

To Find:

The position of zero-order and tenth-order fringes if wavelength used is 7.50X 10⁻⁷m

Solution:

The reading of the micrometer for zero-order is not zero,

⇒ There is a zero error which is equal to = 1.25 mm

 

The distance between zero-order and 10th order fringe = y 10 = 2.37mm−1.25mm

=1.12mm

The position of nth order fringe = yn = $\frac{n\lambda D}{d}$

Here, n= order of the fringe

λ = wavelength of the light used

D = Distance between the source and the screen

d= distance between the slits

Since D and d are constants,

→  $\frac{\triangle y_n}{y_n} = \frac{\triangle \lambda}{\lambda}$

Substituting Δλ  = 7.50X 10⁻⁷m - 5.90 X 10⁻⁷m = 1.60 X 10⁻⁷m

and λ=5.90 X 10⁻⁷m,

Δyn = 0.27 yn

⇒ y′n = yn + Δyn

=yn + 0.27 yn = 1.27 yn

So for n = 10, y'10 = 1.27 X 1.12 = 1.42mm

Adding the zero error of the micrometer gives the new position of 10th order fringe = 1.25 + 1.42 = 2.67mm

Since n = 0 for the zero-order fringe, its position remains the same.

Hence, the new position of the zero-order and the 10th fringe will be 1.25mm and 2.67mm respectively.