Tag: physics

Questions Related to physics

The unit of frequency is:-

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. Hertz

  2. Joule

  3. Ohm

  4. Kilo Calorie

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Correct Option: A
Explanation:

Frequency is the number of complete vibrational cycles of a medium per a given amount of time. The frequency would have units of cycles/second, waves/second or vibrations/second. The unit for frequency is the Hertz (abbreviated Hz) where 1 Hz is equivalent to 1 cycle/second. 

Hertz stands for:

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. second

  2. second$^{-1}$

  3. meter

  4. meter$^{1}$

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Correct Option: B
Explanation:

Hertz is the unit of frequency and frequency is defined as number of vibrations per second ,

        $f=$number of vibrations/ time (in second) ,
which gives frequency in,
$second^{-1}=Hertz$ 

An object oscillates 50 times in one second. What would be its frequency?

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. 0.2 hz

  2. 0.02 hz

  3. 0.002hz

  4. 50Hz

Show answer
Correct Option: D
Explanation:

Frequency is defined as the number of oscillations in one second , as the given object is oscillating , 50 times in one second therefore its frequency is 50 Hz .

Fill in the blank.

The time taken by ___ oscillation  to complete is called time period. 

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. One

  2. Two

  3. Three

  4. Four

Show answer
Correct Option: A
Explanation:
Time period can be defined as time to complete one full oscillation. Hence A is the correct answer. 

The sound from a mosquito is produced when it vibrates its wings at an average rate of $500$ vibrations per second. What is the time period of the vibration?

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. 0.001

  2. 0.002

  3. 0.003

  4. 0.004

Show answer
Correct Option: B
Explanation:

Frequency equals the number of waves that passes a given point per second or the number of oscillations of a vibrating body per second or number of cycles per second.
In this case, a mosquito vibrates its wings at an average rate of 500 vibrations per second. Therefore, the frequency of the sound is 500 Hz.
Time period of the wave is defined as the reciprocal of the frequency of the wave.
That is, $T=\frac { 1 }{ f } =\frac { 1 }{ 500 } =0.002\quad second$.
Hence, time period of the sound produced by the mosquito is 0.002 second.

An object attached to one end of a spring makes 20 vibrations in 10s. Its frequency is

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. 2Hz

  2. 10s

  3. 0.05Hz

  4. 2s

Show answer
Correct Option: A
Explanation:

Answer is A.

The frequency (f) of a wave is the number of full wave forms generated per second. This is the same as the number of repetitions per second or the number of oscillations per second.  
In this case, an object attached to one end of a spring makes 20 vibrations in 10 s. That is, 20 vibration in 10 seconds. S in one second it makes 2 vibrations. 
Therefore, the frequency of the object is 2 Hertz.

The number of cycles an oscillator completes in each second is called its _______________.

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. Frequency

  2. Velocity

  3. Amplitude

  4. Angular velocity

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Correct Option: A
Explanation:

The number of cycles an oscillator completes in each second is called its frequency.
The frequency (f) of a wave is the number of full wave forms generated per second. This is the same as the number of repetitions per second or the number of oscillations per second.  

Which is true for a wave ? (here n = frequency, T = time period)

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. nT$=1$

  2. $\displaystyle\frac{n}{T}=2$

  3. n=T

  4. None of these

Show answer
Correct Option: A
Explanation:

Frequency is , number of vibrations per (one) second , and time period is the time taken to complete one vibration .

      Let a vibrating body completes n vibrations in 1 s ,
therefore time taken to complete one vibration , $T=(1/n)$ second
  therefore we have , $T=1/n$ ,

            or                  $nT=1$

What is the time period of a wave having frequency of 50 Hz?

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. 0.02 s

  2. 0.20 s

  3. 2.0 s

  4. 20 s

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Correct Option: A
Explanation:

$\text {Time period} = \dfrac{1}{\text{frequency}}= \dfrac{1}{50}=\ 0.02 \ s$

A sound wave completes $24$ cycles in $0.8\;s$. The time period of the wave would be:

physics sound: production of sound oscillation - amplitude, time period and frequency of oscillation time period, frequency and amplitude of sound oscillatory and periodic motion

  1. $1/30\;s$

  2. $30\;s$

  3. $1/24\;s$

  4. $24\;s$

Show answer
Correct Option: A
Explanation:

A time period is the time taken to complete one cycle.


Given that, the sound wave completes $24$ cycles in $0.8\,s$

So, the time taken to complete one cycle $=\dfrac{0.8}{24}=\dfrac{1}{30}\,s$

Hence the time period is $\dfrac{1}{30}\,s$