Tag: physics

Questions Related to physics

A person moving in a car with a velocity of $36kmph $ towards a fort wall blows a horn. If he hears the echo after $3s$, the distance of the wall from him. when he blows then horn (velocity of sound $340ms^P{-1}$)

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

  1. $340m$

  2. $1050m$

  3. $700m$

  4. $525m$

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Correct Option: D

Bats detect the obstacles in their path by receiving the reflected

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

  1. infrasonic waves

  2. ultrasonic waves

  3. micro waves

  4. radio waves

Show answer
Correct Option: B
Explanation:

Answer is B.

Most bats produce echolocation sounds by contracting their larynx (voice box). A few species, though, click their tongues. These sounds are generally emitted through the mouth. Echolocation calls are usually ultrasonic, ranging in frequency from 20 to 200 kilohertz (kHz), whereas human hearing normally tops out at around 20 kHz.
While using echolocation, the bats emit a series of short, high-frequency sounds from their mouths or nostrils that bounce off objects and surfaces and then return to the animals ears. Since high-frequency waves do not diffract, or bend, extensively, these ultrasonic vibrations provide bats with accurate maps of their surroundings. 

Echocardiography is used to diagnose heart diseases which utilises infrasonic waves.

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

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient

Show answer
Correct Option: B
Explanation:

An echocardiogram (also called an echo) is a type of ultrasound test that uses high-pitched sound waves that are sent through a device called a transducer. The device picks up echoes of the sound waves as they bounce off the different parts of your heart. These echoes are turned into moving pictures of your heart that can be seen on a video screen.
Hence, the statement is false.

The frequency of a wave is 5 Hz. It refers to (type of wave) ___________.

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

  1. ultrasonics

  2. microwaves

  3. infrasonics

  4. radio waves

Show answer
Correct Option: C
Explanation:

The waves below the frequency of 20 Hz are infrasonic waves. So, the wave of 5 Hz is also an infrasonic wave.

Sound of frequency below $20 \ Hz$ is called

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

  1. audio sounds

  2. infrasonic

  3. ultrasonic

  4. supersonics

Show answer
Correct Option: B
Explanation:

Sound waves are categorized on the basis of their frequency range.

Sound of frequency below $20 \ Hz$ is called as infrasonic. Sound of frequency above $20 \ kHz$ is called as ultrasonic whereas sound of frequency in between $20 \ Hz$ to $20 \ kHz$ is called as audio sound.

Green house effect is the:

physics energy production

  1. trapping of radiation in the atmosphere

  2. trapping of water molecule in the atmosphere


  3. trapping of gases in the atmosphere

  4. none of the above

Show answer
Correct Option: A
Explanation:

Our atmosphere allows the high frequency radiation (Infrared rays) to pass through it, which comes from sun. This radiation reaches to earth and after some absorption (this radiation is also absorbed and radiated by green house gases), earth reflects back low frequency radiation (Infrared rays) which cannot pass through the atmosphere. This radiation is trapped in our atmosphere and keeps our atmosphere warm, this is called green house effect.

Green house effect was discovered by: 

physics energy production

  1. Fischer

  2. Joseph Lister

  3. Joseph Fourier

  4. None

Show answer
Correct Option: C
Explanation:

Process of warming of planet's surface and its lower atmosphere by the absorption of infrared radiations of long wavelength given out from the surface of a planet is known as green house effect.  In 1824, Joseph Fourier discovered the green house effect.

Which of the following is not a greenhouse gas?

physics energy production

  1. Carbon dioxide

  2. Sulphur dioxide

  3. Methane

  4. Ozone

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Correct Option: B

Ozone layer blocks the radiations of wave length

physics energy production

  1. less than $3 \times 10^{-7}$ m

  2. equal to $3 \times 10^{-7}$ m

  3. more than $3 \times 10^{-7}$ m

  4. All of the above

Show answer
Correct Option: A

Carbon monoxide present in the air is the cause of acid rain.

physics energy production

  1. True

  2. False

  3. Ambiguous

  4. Data insufficient

Show answer
Correct Option: B
Explanation:

false,
pollution from burning of fossil fuels is the major cause of acid rain. The main chemicals in air pollution that create acid rain are sulfur dioxide ($s{o} _{2}$) and nitrogen ($N{o} _{x}$).