Tag: physics

Questions Related to physics

The audible range in humans is ____________.

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. $20 Hz$ to $2000 Hz$

  2. $200 Hz$ to $20,000 Hz$

  3. $20 Hz$ to $20,000 Hz$

  4. $200 Hz$ to $20 kHz$

Show answer
Correct Option: C
Explanation:

the audible range of human ear is $20Hz - 20000Hz$

so the answer is C

Ultrasonic waves.

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. Have a crushing and penetrating power

  2. Bring about biological effect such as maiming a frog

  3. Influence chemical reactions

  4. All the above

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Correct Option: D

The range of the wavelength of audible sound that travels with a velocity of 330 m s$^{-1}$ at 0$^{\circ}$ C is 16.5 m - 16.5 mm.

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

$\displaystyle \lambda = \left ( \frac{330}{20} m - \frac{330}{20 \times 10^3} m \right )$
$=(16.5m - 16.5 mm)$

The sound intensity is 0.008 $W/m^2$ at a distance of 10 m from an isotropic point source of power of the source is approximately :

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. 2.5 watt

  2. 0.8 watt

  3. 8 watt

  4. 10 watt

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Correct Option: D

A train running at 108 km/hr towards east whistles at a frequency of 800 Hz. The frequencies heard by a passenger sitting in the train and a person standing near the track whom the train has just passed (Speed of Sound = 330 m/s) 

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. 800 Hz, 733 Hz

  2. 740 Hz, 800 Hz

  3. 800 Hz, 880 Hz

  4. 800 Hz, 750 Hz

Show answer
Correct Option: B

The driver of a car travelling at the speed of $30m/sec$ towards a hill sounds a horn of frequency $600\ Hz$. If the velocity of sound in air is $330m/s$, the frequency of reflected sound as heard by the driver is

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. $500\ Hz$

  2. $550\ Hz$

  3. $555.5\ Hz$

  4. $720\ Hz$

Show answer
Correct Option: D

Ultrasonic, intrasonic and audible waves travel through a medium with speeds $V _u,V _i,$ and $V _a$ respectively, then (given constant temperature)

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. $V _i=V _a=V _u$

  2. $V _u>V _a>V _i$

  3. $V _u < V _a < V _i $

  4. ${ V } _{ a }\le { V } _{ u }={ V } _{ i }$

Show answer
Correct Option: A

A man fires a gun and hears the echo after $2\,\frac{1}{2}sec$. If the velocity of sound in air is $340ms^{-1}$ his distance from the cliff causing the echo is 

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. $2\,\frac{1}{2}km$

  2. $425m$

  3. $850m$

  4. $136m$

Show answer
Correct Option: B

A sound wave of pressure amplitude $5$ pascal propagates through the air medium. The normal pressure of air is $1.0\times10^5 N/m^2$. The difference between maximum and minimum pressure in the medium is 

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. $5\times10^5 N/m^2$

  2. $10\times10^5 N/m^2$

  3. $10 N/m^2$

  4. $None\ of\ these$

Show answer
Correct Option: C

A siren emitting a sound of frequency $1000 Hz$ moves away from you towards a cliff at a speed of $10 m/s$ [speed of sound in air $330 m/s$] Then. 

physics range of hearing sound: production of sound audible, infrasonic and ultrasonic sounds different sounds

  1. The frequency of the sound you hearing coming directly from the siren is $ \dfrac {33}{34} \times 1000 Hz $.

  2. The frequency of the sound you hearing coming directly from the siren is $ \dfrac {33}{32} \times 1000 Hz $.

  3. The frequency of the sound you hear reflect off the cliff $ \dfrac {33}{32} \times 1000 Hz $.

  4. The frequency of the sound you hear reflect off the cliff $ \dfrac {33}{34} \times 1000 Hz $.

Show answer
Correct Option: C