10.4 In a Young’s double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of light used in the experiment.
10.4 In a Young’s double-slit experiment, the slits are separated by 0.28 mm and the screen is placed 1.4 m away. The distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of light used in the experiment.
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1 Answer
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10.4 Distance between the slits, d = 0.28 mm = 0.28 m
Distance between the slits and the screen, D = 1.4 m
Distance between the central bright fringe and the fourth ( n = 4) fringe, u = 1.2 cm = 1.2 m
In case of a constructive interference, we have the relation for the distance between two fringes as : u = n where n = order of fringes = 4 and = wavelength of the light used
Hence, = = = 6 m = 600 m = 600 nm
Hence, wavelength of the light is 600 nm.
Similar Questions for you
At lower end
Tension, T? = 2g = 20 N (due to the 2 kg block)
Velocity, v? = √ (T? /μ) = √ (20/μ)
Wavelength, λ? = 6 cm
At upper end
Tension, T? = (2 kg + 6 kg)g = 8g = 80 N (due to the block and the rope)
Velocity, v? = √ (T? /μ) = √ (80/μ) = √4 * √ (20/μ) = 2v?
Since frequency (f) remains the same:
f = v? /λ? = v? /λ?
⇒ λ? = λ? * (v? /v? )
⇒ λ? = λ? * (2v? /v? ) = 2λ?
⇒ λ? = 2 * 6 cm = 12 cm
β = λD / (d? + a? sinωt)
β? - β? = λD/ (d? - a? ) - λD/ (d? + a? )
= λD [ (d? + a? ) - (d? - a? ) / (d? ² - a? ²) ]
= 2λDa? / (d? ² - a? ²)
3d = 0.6mm
D = 80cm
= 800mm
Path difference is given by
BP – Andhra Pradesh = Dx
[for Dark fringe at P]
n = 0, for first dark fringe
first dark fringe is observed on the screen directly opposite to one of the slits]
The distance between two successive bright fringes is fringe width .
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