Define the ‘frequency’ and ‘time-period’ of a wave. What is the relation between the two?
Answer
The number of complete waves (or cycles) produced in one second is called frequency of the wave. The time required to produce one complete wave (or cycle) is called time-period of the wave. The time taken to complete one vibration is called time-period. Relation between time-period an frequency of a wave is: $\text{Frequency}=\frac{1}{\text{time period}}$
One way is with a depth gauge. The gauge basically measure differential pressure between pressure inside the boat (kept at atmospheric pressure) and sea pressure outside). Knowing how fast pressure rises as depth increases allows the gauge indication to be calibrated to read out in feet of depth.
Given below are some example of wave motion. State in case, if the wave motion is transverse, longitudinal or a combination of both? Light waves travelling from Sun to Earth.
Answer
Transverse, because the light waves are electromagnetic waves in which electric and magnetic fields oscillate in the direction at right angles to each other and also to the direction of propagation of the wave.
Given below are some example of wave motion. State in case, if the wave motion is transverse, longitudinal or a combination of both? Ultrasonic waves in air produced by a vibrating quartz crystal.
Answer
Longitudinal, because the direction of vibration of air molecules is to and fro about its mean position along the direction of propagation of wave due to the vibration of quartz crystal.
What will be the change in the wavelength of a sound wave in air if its frequency is doubled?
Answer
Velocity of sound = Frequency × wavelength Speed of sound in air is constant. Hence, frequency × wavelength = constant If frequency is doubled, wavelength is reduced to half.
State one observation from everyday life which shows that sound travels much more slow than light.
Answer
It is common observation that in the rainy season, the flash of lightning is seen first and the sound of thunder is heard a little later. That’s because, speed of light is very high as compared to speed of sound in air.
Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a percussion mallet, to produce sound.
Given below are some example of wave motion. State in case, if the wave motion is transverse, longitudinal or a combination of both? Wave produced in a cylinder consisting a liquid by moving its piston back and forth.
Answer
Longitudinal, because the molecules of the liquid vibrate to and fro about their mean positions along the direction propagation of the wave.
Name the characteristic of sound which can distinguish between the ‘notes’ (musical sounds) played on a flute and a sitar (both the notes having the same pitch and loudness).
How does the velocity of sound change when medium changes from air to water?
Answer
When sound travels from one medium to another, both its velocity and wavelength undergo changes. Thus, if the velocity of sound doubles when it travels from one medium to another, its wavelength also doubles. The frequency of sound depends upon the source of sound, not the medium of propagation.
What conclusion can be obtained from the observation that when the prongs of a sound making tuning fork touch the surface of water in a beaker, the water gets splashed?
Answer
The conclusion from the observation is that the prongs of tuning fork are vibrating, and the vibrating prongs carry energy which gets transmitted to surrounding medium.