A train moves towards a stationary observer at 50 m/s. The train sounds a whistle and its frequency is registered by the observer as . If the train's speed is increased by 25 m/s, the frequency registered is . If the speed of sound is 300 m/s, then : is:
1. 3:5
2. 5:7
3. 7:9
4. 9:10
1. | \(l\) | 2. | \(2l\) |
3. | \(3l\) | 4. | \(4l\) |
1. | Wavelength of the component waves is \(10~\text{cm}.\) |
2. | The separation between a node and the nearest antinode is \(2.5~\text{cm}.\) |
3. | Frequency of the component wave is \(0.25~\text{Hz}\). |
4. | All of these |
1. | \(6\) | 2. | \(5\) |
3. | \(4\) | 4. | \(3\) |
1. | \(1:1\) | 2. | \(5:2\) |
3. | \(3:2\) | 4. | \(4:5\) |
A car with a siren is moving towards a hill at a speed of 108 km/h. A person is standing at the foot of the hill. The frequency observed by a person is: (frequency of siren is 600 Hz, velocity of sound is 330 m/s)
1. 720 Hz
2. 660 Hz
3. 600 Hz
4. 630 Hz
1. | The velocity of the component wave is \(0.5~\text{cm/s}\). |
2. | The amplitude of one of the component waves is \(6~\text{cm}\). |
3. | The distance between two consecutive nodes is \(0.5~\text{cm}\). |
4. | \(x= 0.25~\text{cm}\) is the first node except the nodes at the ends. |