Home
Class 12
PHYSICS
Sound with intensity larger than 120 dB ...

Sound with intensity larger than 120 dB appears painful to a person. A small speaker delivers 2.0 W of audio output. How close can the person get to the speaker without hurting his ears ?

Text Solution

Verified by Experts

`1/sqrtpi m`
Promotional Banner

Topper's Solved these Questions

  • WAVE MOTION AND SOUND

    AAKASH SERIES|Exercise PROBLEMS (LEVEL - I)|59 Videos

  • WAVE MOTION

    AAKASH SERIES|Exercise PRACTICE SHEET ADVANCED (INTEGER TYPE QUESTIONS)|10 Videos

  • WAVE OPTICS

    AAKASH SERIES|Exercise PROBLEMS (LEVEL - II)|33 Videos

Similar Questions

Explore conceptually related problems

A microphone of cross sectional area 0.80 cm^2 is placed in front of a small speaker emitting 3.0 W of sound output. If the distance between the microphone and the speaker is 2.0 m how much energy falls on the microphone in 5.0 s?

A small speaker delivers 2 W of audio will one detect 120 dB intensity sound ? [Given reference intensity of sound as 10^(-12) W//m^(2) ]

(a) What is the intensity of a 60 dB sound ? (b) If the sound level is 60 dB close to a speaker that has an area of 120 cm ^(2) . What is the acoustic power output of the speaker?

It is desired to measure the magnitude of field between the poles of a powerful loud speaker magnet. A small flat search coil of area 2 cm^(2) with 25 closely wound turns is positioned normal to the field direction and then quickly snatched out of the field region (Equivalently, one can give it a quick 90^(@) turn to bring its plane parallel to the field direction). The total charge flowing in the coil (mesured by a ballistic galbanometer connected to the coil) is 7.5 mC. The resistance of the coil and galvanometer is 0.5 Omega . Estimate the field strength of the magnet.

An oscillator of frequency 680 Hz drives two speakers . The speakers are fixed on a vertical pole at a distance 3 m from each other as shown in Fig. 7.103. A person whose height is almost the same as that of the lower speaker walks towards the lower speaker in a direction perpendicular to the pole. Assuming that there is no reflection of sound from the ground and speed of sound is v = 340 m//s , answer the following questions. At some instant , when the person is at a distance 4 m from the pole , the wave function ( at the person's location) that describes the waves coming from the lower speaker y = A cos (kx - omega t) , where A is the amplitude , omega = 2 pi v with v = 680 Hz (given) and k = 2 pi//lambda Wave function ( at the person's location) that describes waves coming from the upper speaker can be expressed as :

Two sound speakers are driver in phase by an audio amplifier at frequency 600 H_(Z) . The speed of sound is 340 m//s . The speakers are on the y - axis, one at y = + 1.0 m and the other at y = - 1.0 m . A listener begins at y = 0 and walks along a line parallel to the y - axis at a very large distance x away. (a) At what angle theta (between the line from the origin to the listener at the x - axis) will she first hear a minimum sound intensity? (b) At what angle will she first hear a maximum (afer theta = o^(@) ) sound intensity? (c ) How many maxima can she possible hear if she keeps walking in the same direction?

When a sound wave enters the ear, it sets the eardrum into oscillation, which in turn causes oscillation of 3 tiny bones in the middle ear called ossicles. This oscillation is finally transmitted to the fluid filled in inner portion of the ear termed as inner ear, the motion of the fluid disturbs hair cells within the inner ear which transmit nerve impulses to the brain with the information that a sound is present. The theree bones present in the middle ear are named as hammer, anvil and stirrup. Out of these the stirrup is the smallest one and this only connects the middle ear to inner ear as shown in the figure below. The area of stirrup and its extent of connection with the inner ear limits the sensitivity of the human ear consider a person's ear whose moving part of the eardrum has an area of about 50mm^2 and the area of stirrup is about 5mm^2 . The mass of ossicles is negligible. As a result, force exerted by sound wave in air on eardum and ossicles is same as the force exerted by ossicles on the inner ear. Consider a sound wave having maximum pressure fluctuation of 4xx10^-2Pa from its normal equilibrium pressure value which is equal to 10^5Pa . Frequency of sound wave in air is 332(m)/(s) . Velocity of sound wave in fluid (present in inner ear) is 1500(m)/(s) . Bulk modulus of air is 1.42xx10^5Pa . Bulk modulus of fluid is 2.18xx10^9Pa . Q. This person (without hearing aid machine) is sitting inside a busy restaurant where average sound intensity is 3.2xx10^-5(W)/(m^2) . How much energy in the form of sound is taken up by the person in his meal time of 1 h?

AAKASH SERIES-WAVE MOTION AND SOUND-PROBLEMS (LEVEL - II)
  1. Two identical tuning forks vibrating at the same frequency 256 Hz are ...

    Text Solution

    |

  2. Two sound sources are moving in opposite directions with velocities v...

    Text Solution

    |

  3. A 300 Hz source, an observer and wind are moving as shown in the figur...

    Text Solution

    |

  4. A person standing on a road sends a sound signal to the driver of a ca...

    Text Solution

    |

  5. A stationary sound sound 's' of frequency 334 Hz and a stationary ovs...

    Text Solution

    |

  6. Spherical waves are emitted from a 1.0 W source in an isotropic non-ab...

    Text Solution

    |

  7. The intensity of sound from a point source is 1.0 xx 10^-8 Wm^-2, at a...

    Text Solution

    |

  8. Most people interpret a 9.0 dB increase in sound intensity level as a ...

    Text Solution

    |

  9. About how many times more intense will the normal ear perceiver a soun...

    Text Solution

    |

  10. The explosion of a fire cracker in the air at the a heigth of 40 m pro...

    Text Solution

    |

  11. The sound level at a point 5.0 m away from a point source is 40 dB. Wh...

    Text Solution

    |

  12. If the intensity of sound is doubled, by how many decibels does the so...

    Text Solution

    |

  13. Sound with intensity larger than 120 dB appears painful to a person. A...

    Text Solution

    |

  14. Two waves, each having a frequency of 100 Hz and a wavelength of 2.0 c...

    Text Solution

    |

  15. Two waves, each having a frequency of 100 Hz and a wavelength of 2.0 c...

    Text Solution

    |

  16. Two waves, each having a frequency of 100 Hz and a wavelength of 2.0 c...

    Text Solution

    |

  17. Three component sinusoidal waves progressing in the same directions al...

    Text Solution

    |

  18. A soldier walks towards a high wall taking 120 steps per minute. When ...

    Text Solution

    |

  19. A man stands before a large wall at a distance of 50.0m and claps his ...

    Text Solution

    |

  20. A road runs midway between two parallel rows of buildings. A motorist ...

    Text Solution

    |