Concepts Of Physics MCQ Edition [Volume 1]PhysicsWave Motion and Waves on a String
Two waves propagating in the same direction through the same region possess equal frequencies, wavelengths, and amplitudes. If each wave has an amplitude of 4 mm and the phase difference between the waves is 90^ , what is the resultant amplitude?
Options
- A4 mm
- B4 2 mm
- C8 mm
- D2 2 mm
Correct answer
B. 4 2 mm
Step-by-step solution
The resultant amplitude A_R of two waves with amplitudes A₁ and A₂ and a phase difference is given by: A_R = A₁^2 + A₂^2 + 2A₁A₂ Given A₁ = A₂ = 4 mm and = 90^ . Substituting the values: A_R = 4^2 + 4^2 + 2(4)(4) 90^ Since 90^ = 0 : A_R = 16 + 16 + 0 = 32 = 4 2 mm