Question

Two waves represented by y₁ = 10 Sin (2000 π t) and y₂ = 10 sin (2000 π t + π/2) are superposed at any point at a particular instant. The resultant amplitude is

• A. 10 units
• B. 20 units
• C. 14.1 units
• D. Zero

Answer 1

Answer: (C)

14.1 units

Answer 2

The resultant amplitude A of two waves of amplitudes a₁ and a_­2 and phase difference φ is ($(a_{1}^{2} + a_{2}^{2} + 2a_{1}a_{2}\cos\varphi)^{1/2}$. Substituting a₁ = 10, a₂ = 10 and φ = 90⁰, we get A = 14.1.