Frequency

Q.

What is the relationship between wavelength and frequency in a medium?

1. Wavelength is directly proportional to the frequency.

2. Wavelength is inversely proportional to the frequency.

3. There is no relationship between wavelength and frequency.

4. Wavelength is always twice the frequency.

Q.

What is the SI Unit of Frequency?

Q.

Explain the difference between low pitched and high pitched sound using diagrams. [3 MARKS]

Q.

A sound wave travels at a speed of $339m/s$. If its wavelength is $1.5cm$, what is the frequency of the wave? Will it be audible?

Q. Given that sound travels in air at 340 ms${}^{-1}$, find the wavelength of the waves in air produced by the 20 kHz sound source.If the same source is put in a water tank, what would be the wavelength of the sound waves produced in water? Speed of sound in water = 1480 ms${}^{-1}$.

Q.

The number of waves passing through a point in one second is called frequency.

1. True
2. False

Q.

The heart of a man beats 75 times a minute. What is its (a) frequency and (b) time period ?

Q.

Define the 'frequency' and 'time - period' of a wave. What is the relation between the two ?

Q.

Sound waves with frequency smaller than 20 Hz are called:

1. ultrasound

2. infrasound

3. nanosound

4. minisound

Q. Sound produced by the heart beats (72 times a minute) has frequency of:

1. In audible range of Human being
2. More than the audible range of Human being
3. Less than the Audible range of Human being
4. None of these

Q. If a sound wave has frequency of 30 Hz, then it will vibrate _____ times in $\frac{1}{2}$ minute.

1. 1800
2. 15
3. 900
4. 60

Q.

How is the frequency of a wave related to its time period ?

Q.

What do you mean by the term frequency of a wave ? State its S.I. unit.

Q.

Calculate the frequency of a wave whose time period is 0.02 s.

Q.

The number of oscillations completed per second is called

Q.

Name the physical quantity whose SI unit is 'hertz'.

Q.

What are sonic waves?

Q.

How are the wave velocity V, frequency f and wavelength $\lambda$ of a wave related ? Derive the relationship.

Q.

Given below are two statements:

Statement (1):- A second’s pendulum has a time period of$1$ second.

Statement (2):- It takes precisely one second to move between the two extreme positions.

In light of the above statements, choose the correct answer from the options given below.

1. Both Statement I and Statement II are false

2. Statement I is true but Statement II is false

3. Statement I is false but Statement II is true

4. Both Statement I and Statement II is true

Q.

Choose the correct option relating wavelengths

1. ${\lambda }_{radiowaves}>{\lambda }_{microwaves}>{\lambda }_{visible}>{\lambda }_{x-rays}$

2. ${\lambda }_{visible}>{\lambda }_{x-rays}>{\lambda }_{radiowaves}>{\lambda }_{microwaves}$

3. ${\lambda }_{visible}<{\lambda }_{microwaves}<{\lambda }_{radiowaves}<{\lambda }_{x-rays}$

4. ${\lambda }_{x-rays}<{\lambda }_{microwaves}<{\lambda }_{radiowaves}<{\lambda }_{visible}$

Q.

Which of the following remains unchanged when a sound wave travels from air to water?

1. Wavelength

2. Amplitude

3. Frequency

4. Speed

Q. What is the frequency of car horn?

Q.

If 20 waves are produced per second, what is the frequency in hertz?

Q. A source of sound produces waves of wavelength 60 cm when it is stationary. If the speed of sound in air is 320 m/s and source moves with speed 20 m/s, the wavelength of sound in the forward direction will be approximately:

1. 56.2 cm
2. 60.8 cm
3. 64.4 cm
4. 68.6 cm
   

Q. The number of complete waves produced in one second is called .

1. frequency
2. time period
3. wavelength

Q. Sound waves with frequency smaller than 20 Hz are called:

1. ultrasound
2. infrasound
3. nanosound
4. minisound

Q.

What are the properties of sound waves?

Q.

What is intensity of sound?

Q.

Ultrasonic waves are also called supersonic waves.

1. True
2. False

Q. Name the physical quantity whose SI unit is ‘hertz’. Define.