A pipe, \(30.0\) cm long, is open at both ends.
(i) | Which harmonic mode of the pipe resonates a \(1.1\) kHz source? |
(ii) | Will resonance with the same source be observed if one end of the pipe is closed? |
Take the speed of sound in air as \(330\) m s–1.
(i) | (ii) | |
1. | First | No |
2. | Second | No |
3. | First | Yes |
4. | Second | Yes |
Assertion (A): | Sound waves in a gas are pressure waves, but these are also accompanied by changes in local temperature. |
Reason (R): | This is due to the fact that sound waves are propagated in gas through an adiabatic process, and hence accompanied by temperature variations. |
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. |
The figure shows the snapshot of a travelling sine wave in a string. Four elemental portions \(a,b,c\) and \(d\) are indicated on the string. The elemental portion with maximum potential energy is/are:
1. \(a\)
2. \(b\)
3. \(c\)
4. \(b \text{ and } d\)
Assertion (A): | Sound would travel faster on a hot summer day than on a cold winter day. |
Reason (R): | 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. |
Assertion (A): | Where two vibrating tuning forks having frequencies \(256~\text{Hz}\) and \(512~\text{Hz}\) are held near each other, beats cannot be heard. |
Reason (R): | The principle of superposition is valid only if the frequencies of the oscillators are nearly equal. |
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. | Both (A) and (R) are False. |
Assertion (A): | Beats can also be observed by two light sources as in sound. |
Reason (R): | Light sources have constant phase difference. |
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. | Both (A) and (R) are false. |
Assertion (A): | In the case of a stationary wave, a person hears a loud sound at the nodes as compared to the antinodes. |
Reason (R): | In a stationary wave, all the particles of the medium vibrate in phase. |
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. | Both (A) and (R) are false. |
Statement I: | Sound waves travelling from air into water, incident obliquely, bend towards the normal. |
Statement II: | Sound waves travel more slowly in water than in air. |
1. | Statement I is incorrect and Statement II is correct. |
2. | Both Statement I and Statement II are correct. |
3. | Both Statement I and Statement II are incorrect. |
4. | Statement I is correct and Statement II is incorrect. |
Assertion (A): | The flash of lightning is seen before the sound of thunder is heard. |
Reason (R): | Speed of sound is greater than speed of light. |
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. | Both (A) and (R) are false. |
Assertion (A): | Our ears distinguish two notes, one produced by a violin and other by guitar, if they have exactly same intensity and same frequency. |
Reason (R): | When a musical instrument is played, it produces a fundamental note which is accompanied by a number of overtones called harmonics. |
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. | Both (A) and (R) are false. |