| (a) | The wave is travelling from right to left. |
| (b) | The speed of the wave is \(20~\text{m/s}.\) |
| (c) | The frequency of the wave is \(5.7~\text{Hz}.\) |
| (d) | The least distance between two successive crests in the wave is \(5.7~\text{cm}.\) |
| 1. | (a), (c) | 2. | (a), (b), (c) |
| 3. | (b), (d) | 4. | (d) only |
| (A) | It represents a progressive wave of frequency \(60\) Hz. |
| (B) | It represents a stationary wave of frequency \(60\) Hz. |
| (C) | It is the result of the superposition of two waves of wavelength \(3\) m, frequency \(60\) Hz each travelling with a speed of \(180\) m/s in opposite directions. |
| (D) | The amplitude of this wave is constant. |
| (a) | Every particle has a fixed amplitude which is different from the amplitude of its nearest particle. |
| (b) | All the particles cross their mean position at the same time. |
| (c) | All the particles are oscillating with same amplitude. |
| (d) | There is no net transfer of energy across any plane. |
| (e) | There are some particles which are always at rest. |