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A person wears a hearing aid that uniformly increases the sound level of all audible frequencies of sound by 28.1 dB. The hearin

ladessa [460]

Answer:

I₂ = 2.13 x 10⁻⁸ W/m²

Explanation:

given,

increase in sound level = 28.1 dB

frequency of the sound = 250 Hz

intensity = 3.3 x 10⁻¹¹ W/m²

Intensity delivered = ?

the difference of intensity level is give as

$\beta_2-\beta_1 = 10log(\dfrac{I_2}{I_o}) - 10log(\dfrac{I_1}{I_o})$

$\beta_2-\beta_1 = 10(log(\dfrac{I_2}{I_o}) -log(\dfrac{I_1}{I_o}))$

$\beta_2-\beta_1 = 10(log(\dfrac{I_2}{I_1})$

$28.1= 10(log(\dfrac{I_2}{I_1})$

$log\dfrac{I_2}{I_1}=2.81$

$\dfrac{I_2}{I_1}=10^{2.81}$

I₂ = 645.65 I₁

I₂ = 645.65 x 3.3 x 10⁻¹¹

I₂ = 2.13 x 10⁻⁸ W/m²

4 0

2 years ago

The Hubble Space Telescope orbits the Earth at approximately 612,000m altitude. Its mass is 11,100 kg and the mass of earth is 5

nexus9112 [7]

Answer:

7.55 km/s

Explanation:

The force of gravity between the Earth and the Hubble Telescope corresponds to the centripetal force that keeps the telescope in uniform circular motion around the Earth:

$G\frac{mM}{R^2}=m\frac{v^2}{R}$

where

$G=6.67\cdot 10^{-11} m^3 kg^{-1} s^{-2}$ is the gravitational constant

$m=11,100 kg$ is the mass of the telescope

$M=5.97\cdot 10^{24} kg$ is the mass of the Earth

$R=r+h=6.38\cdot 10^6 m+612,000 m=6.99\cdot 10^6 m$ is the distance between the telescope and the Earth's centre (given by the sum of the Earth's radius, r, and the telescope altitude, h)

v = ? is the orbital velocity of the Hubble telescope

Re-arranging the equation and substituting numbers, we find the orbital velocity:

$v=\sqrt{\frac{GM}{R}}=\sqrt{\frac{(6.67\cdot 10^{-11})(5.97\cdot 10^{24} kg)}{6.99\cdot 10^6 m}}=7548 m/s=7.55 km/s$

6 0

2 years ago

Materials in which electric charges move freely such as copper and aluminum are called

yuradex [85]

Answer:

Conductors allow electric charges to move freely

8 0

3 years ago

The nervous system has two distinct branches. They are the:

Troyanec [42]

Answer:

central nervous system

peripheral nervous system

Explanation:

The nervous system has two main parts: The central nervous system is made up of the brain and spinal cord. The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.Oct 1, 2018

3 0

2 years ago

Read 2 more answers

A car accelerates from rest at 3.6 m/s 2 . How much time does it need to attain a speed of 5 m/s?

Olenka [21]

car starts from rest

$v_i = 0$