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2 years ago

an electromagnetic wave has an electric field with peak value 120. What is the averge energy delievered to a surface

Physics

1 answer:

lianna [129]2 years ago

7 0

Answer:

The average energy delivered to a surface is 19.116 W/m².

Explanation:

Given;

maximum electric field, E₀ = 120 v/m

The average energy delivered by the wave to a surface is given by

$I_{avg} = \frac{c\epsilon_ o E_o^2}{2}$

where;

c is the speed of light, = 3 x 10⁸ m/s

ε₀ is the permittivity of free space = 8.85 x 10⁻¹² c²/Nm²

$I_{avg} = \frac{c\epsilon_ o E_o^2}{2} \\\\I_{avg} = \frac{(3*10^8)(8.85*10^{-12})( 120)^2}{2}\\\\ I_{avg} =19.116 \ W/m^2$

Therefore, the average energy delivered to a surface is 19.116 W/m².

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alina1380 [7]

The correct answer in this case is B. Harmonic.

The remaining answers refer to other parts of a musical composition, and some such as the pitch can even be found in the study of human voice.

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3 years ago

How would the terminal velocity of a piece of tissue paper compare to the terminal velocity of a rock?

matrenka [14]

Answer: Rock require larger drag force and to achieve it rock need to move at a very high terminal velocity.

Explanation: Terminal velocity is defined as the final velocity attained by an object falling under the gravity. At this moment weight is balanced by the air resistance or drag force and body falls with zero acceleration i.e. with a constant velocity.

Case 1: Terminal velocity of a piece of tissue paper.

The weight of tissue paper is very less and it experiences an air resistance while falling downward under the effect of gravity.

Downward gravitational force, F = mg

Upward air resistance or friction or drag force will be $f_{1}$

So, paper will attain terminal velocity when mg = $f_{1}$

Case 2: Rock is very heavy and require larger air resistance to balance the weight of rock relative to the tissue paper case.

Downward force on rock, F = Mg

Drag force = $f_{2}$

Rock will attain terminal velocity when Mg = $f_{2}$

Mg > mg

so, $f_{2}$ > $f_{1}$

And rock require larger drag force and to achieve it rock need to move at a very high terminal velocity.

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3 years ago

A single-slit diffraction pattern is formed on a distant screen. Assuming the angles involved are small, by what factor will the

Novay_Z [31]

Answer:

It will be cut in half

Explanation:

The diffraction of a slit is given by the formula

a sin θ = m where

a = width of the slit,

λ = wavelength and

m = integer that determines the order of diffraction.

Next we divide both sides by a, we have

sin θ = m λ / a

Also, recall that

a’ = 2 a

Then we substitute in the previous equation

2asin θ' = m λ, if divide by 2a, we have

sin θ' = (m λ / 2a).

Now again, from the first equation, we said that sin θ = m λ / a, so we substitute

sin θ ’= sin θ / 2

Then we use trigonometry to find the width, we say

tan θ = y / L

Since the angle is small, we then have

tan θ = sin θ / cos θ

tan θ = sin θ, this then means that

sin θ = y / L

we will then substitute

y’ / L = y/L 1/2

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this means that when the slit width is doubled the pattern width will then be halved

4 0

3 years ago

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

Solnce55 [7]

I think the correct answer is D: Potential Energy.

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3 years ago

Read 2 more answers

Part A

geniusboy [140]

Answer:

a) b = -5

b) slope = 3/2

Explanation:

a) The equation of a line is given as y = mx + b, where m is the slope of the line and b is the intercept on the y axis.

Given that y = 3x + b and it passes through the point (2, 1). Hence when x = 2, y = 1. Therefore, substituting for x and y:

1 = 3(2) + b

1 = 6 + b

b = 1 - 6

b = -5

b) The equation of a line passing through two points ( $x_1,y_1$ ) and $x_2,y_2$ is given by:

$y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)$

The equation of the line passing through the two points (0,3) and (4,9) is:

$y-3=\frac{9-3}{4-0}(x-0)\\ \\y-3=\frac{3}{2}x\\ \\y = \frac{3}{2}x+3$

Comparing y = (3/2)x + 3 with y = mx + b, the slope (m) is 3/2

4 0

2 years ago