| 1. | \(\dfrac{A}{\sqrt{r}} \sin (k r-\omega t)\) | 2. | \(\dfrac{A}{{r}} \sin (k r-\omega t)\) |
| 3. | \(Ar \sin (k r-\omega t)\) | 4. | \(\dfrac{A}{{r^2}} \sin (k r-\omega t)\) |

| 1. | maximum at \(A,\) minimum at \(O\) |
| 2. | minimum at \(A,\) maximum at \(O\) |
| 3. | uniform |
| 4. | minimum at \(A\) and \(O,\) maximum in the middle |
| (a) | \(\dfrac{\partial y}{\partial t}=\left ( \dfrac{\omega }{k} \right )^{2}\dfrac{\partial y}{\partial x} \) |
| (b) | \(\dfrac{\partial^{2}y}{\partial t^{2}}=\left ( \dfrac{\omega }{k} \right )^{2}\dfrac{\partial^{2}y}{\partial x^{2}}\) |
| 1. | only (a) | 2. | only (b) |
| 3. | both (a) and (b) | 4. | neither (a) nor (b) |
| Assertion (A): | Sound travels faster on a hot summer day than on a cold winter day. |
| Reason (R): | The velocity of sound is directly proportional to the square root of its absolute temperature. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
| 1. | first harmonic |
| 2. | second harmonic |
| 3. | third harmonic |
| 4. | fourth harmonic |
Which of the following is a mechanical wave?
1. Radio waves
2. \(X\text-\)rays
3. Light waves
4. Sound waves
| 1. | \(2 \pi\) cm | 2. | \(5 \pi\) cm |
| 3. | \(\pi\) cm | 4. | \({\dfrac {5 \pi} 2}\) cm |