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PHY 104 PHY 104 Past Questions Objective Question
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Question

A beam of light of wavelength 650 nm is used to obtain interference fringes. The distance between the slits is 2.0 mm and the distance between the plane of the slits and the screen is 120 cm. Find the distance of the third bright fringe on the screen from the central maxima.
Options
A 7.8 × 10⁻⁴ m
B 7.8 × 10⁻³ m
C 1.17 × 10⁻³ m
Correct Answer
D 1.17 × 10⁻⁴ m
Correct Answer

Option C is the correct answer.

Detailed Explanation

The position of bright fringes is y = mλL/d. m = 3, λ = 650 × 10⁻⁹ m, L = 1.20 m, d = 2.0 × 10⁻³ m. y = (3 × 650e-9 × 1.20) / 2.0e-3 = 2340e-9 / 2.0e-3 = 1.17 × 10⁻³ m.

Hint

Use y = mλL/d for bright fringes.

Question Info

Course: PHY 104
Topic: PHY 104 Past Questions
Type: Objective
Difficulty: Not specified
Question 847 of 947
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