Periodic Motion & SHM Basics question from MHT CET 2025 (25 Apr, Shift 1)

Answer: (c)

1. Phase gained $= \frac{2\pi t}{T}$. A completes 2 oscillations, so $t = 2T$.
2. $\phi_A = 2\pi(2) = 4\pi$, $\phi_B = \frac{2\pi(2T)}{3T/2} = \frac{8\pi}{3}$
3. $\Delta\phi = 4\pi - \frac{8\pi}{3} = \frac{4\pi}{3}$
4. So the answer is (c) $\frac{4\pi}{3}$.