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2 years ago

Many older people become farsighted as ?

Physics

1 answer:

Katyanochek1 [597]2 years ago

7 0

Answer:

Presbyopia occurs when the aging lens of your eye becomes less flexible and can no longer focus on objects up-close. Think of your eye like a camera. The lens in the camera has the ability to autofocus on objects whether they are near or far. The lens in your eye works much the same way.

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What does muttered mean

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Muttered is the same thing like mumble. It's like when you are speaking and no one couldn't hear what you said. So Muttered is when you say something low .

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What type of charge does an electron have?

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3 years ago

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Two identical blocks, A and B, are on a horizontal surface, as shown above. There is negligible friction between the surface and

e-lub [12.9K]

Answer:

the speed of the center of mass stays the same

Explanation:

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2 years ago

A concert loudspeaker suspended high off the ground emits 34 W of sound power. A small microphone with a 1.0 cm2 area is 44 m fr

rjkz [21]

Answer:

Part A

I = 1.4 mW/m²

Part B

β = 91.46 dB

Explanation:

Part A

Sound intensity is the power per unit area of sound waves in a direction perpendicular to that area. Sound intensity is also called acoustic intensity.

For a spherical sound wave, the sound intensity is given by;

$I = \frac{P}{A}$

$I = \frac{P}{4\pi r^{2}}$

Where;

P is the source of power in watts (W)

I is the intensity of the sound in watt per square meter (W/m2)

r is the distance r away

Given:

P = 34 W,

A = 1.0 cm²

r = 44 m

The sound intensity at the position of the microphone is calculated to be;

$I = \frac{34}{4\pi (44)^{2}}$

I = 0.0013975 W/m²

≈ I = 0.0014 W/m² = 1.4 × 10⁻³ W/m²

I = 1.4 mW/m²

The sound intensity at the position of the microphone is 1.4 mW/m².

Part B

Sound intensity level or acoustic intensity level is the level of the intensity of a sound relative to a reference value. It is a a logarithmic quantity. It is denoted by β and expressed in nepers, bels, or decibels.

Sound intensity level is calculated as;

β $= 10log_{10}\frac{I}{I_{0}}$ dB