The periodic waves of intensities I₁ and I₂ pass through a region at the same time

⇦

⇨

The periodic waves of intensities I₁ and I₂ pass through a region at the same time in the same direction. The sum of the maximum and minimum intensities is:

Options

(a) I₁ + I₂
(b) (√I₁ + √I₂)²
(c) (√I₁ – √I₂)²
(d) 2 (I₁ + I₂)

Correct Answer:

2 (I₁ + I₂)

Explanation:

The resultant intensity of two periodic waves at a point is given by
I = I₁ + I₂ + 2 √I₁I₂ . cos ?.
Resultant intensity is max. if cos ? = -1
i.e Iₘₐₓ = I₁ + I₂ + 2 √I₁I₂
Resultant intensity is min. if cos ? = +1
i.e, Iₘᵢₙ = I₁ + I₂ – 2 √I₁I₂
Therefore, the sum of the max. and min. intensities is Iₘₐₓ + Iₘᵢₙ
= I₁ + I₂ + 2 √I₁I₂ + I₁ + I₂ – 2 √I₁I₂
= 2 (I₁ + I₂)

Related Questions:

1. Two coherent sources of different intensities send waves which interfere.
2. Two lines of force due to a bar magnet
3. A coin of mass m and radius r having moment of inertia I about the axis passes
4. The induced emf in a coil of 10 H inductance in which current varies
5. The mean free path of electrons in a metal is 4 x 10⁻⁸ m. The electric field

Topics: Ray Optics (94)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends