Electromagnetic waves transport energy. This problem shows you which parts of the energy are stored in the electric and magnetic fields, respectively, and also makes a useful connection between the energy density of a plane electromagnetic wave and the Poynting vector. In this problem, we explore the properties of a plane electromagnetic wave traveling at the speed of light calong the x axis through vacuum. Its electric and magnetic field vectors are as follows:

E= EoSin(kx- ωt)j
B= BoSin (kx- ωt)k

Throughout, use these variables (E, B, Eo, Bo, k, x, and w) in your answers. You will also need the permittivity of free space εo and the permeability of free space μo.

Required:
What is the instantaneous energy μE(t) in the electric field of the wave?

Answers

Answer 1

Answer:

S = (√(ε₀/μ₀)(Eo²Sin²(kx- ωt)i

Explanation:

The instantaneous energy of the wave is given by the Poynting vector, S = 1/μ₀(E × B) where μ₀ = permeability of free space

So, substituting the variables into the equation with E= EoSin(kx- ωt)j and B= BoSin (kx- ωt)k

So,  S = 1/μ₀(E × B)

S = 1/μ₀(EoSin(kx- ωt)j × BoSin (kx- ωt)k)

S = 1/μ₀(EoSin(kx- ωt) × BoSin (kx- ωt) (j × k)

S = 1/μ₀(EoBoSin²(kx- ωt)i  (i = j × k)

Now,

Eo/Bo = c where c = speed of light

So, Bo = Eo/c

Thus

S = 1/μ₀(EoBoSin²(kx- ωt)i

S = 1/μ₀(Eo(Eo/c)Sin²(kx- ωt)i

S = 1/cμ₀(Eo²Sin²(kx- ωt)i

Also,c = 1/√μ₀ε₀ where ε₀ =permittivity of free space

So,

S = 1/cμ₀(Eo²Sin²(kx- ωt)i

S = 1/(1/√μ₀ε₀)μ₀(Eo²Sin²(kx- ωt)i

S = 1/(1/√(ε₀/μ₀)(Eo²Sin²(kx- ωt)i

S = (√(ε₀/μ₀)(Eo²Sin²(kx- ωt)i

which is the instantaneous energy in the electric field.


Related Questions

The bob (weight) at the end of a pendulum has a mass of 0.3 kilograms. The bob is pulled to position B and allowed to swing. It goes all the way to position C and swings
back.
joules. If the maximum height of the bob is 0.45 meters when it swings back,
joules of energy was
The potential energy of the bob at position B is
transformed to thermal energy.
Use g = 9.8 m/s2 and PE = mxgxn.

Answers

Answer: The first box is 1.47

The second box is 1.323

Explanation:

The potential energy of the pendulum bob at position B is 1.323 J.

What is the potential energy of the box of the pendulum?

Potential energy is the energy a body has by virtue of its position or state above the ground.

Potential energy = mass × acceleration due to gravity × height

The mass of the bob = 0.3 kg

height above the ground = 0.45 m

acceleration due to gravity, g = 9.8 m/s^2

Potential energy = 0.3 × 0.45 × 9.8 = 1.323 J

Therefore, the potential energy of the pendulum bob at position B is 1.323 J.

Learn more about potential energy at: https://brainly.com/question/14427111

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Lupus is a temporary disease that can be cured easily. True False​

Answers

Answer:

falseeee

Explanation:

A waterfall is an example of what energy conversion?

Answers

Answer:

most common energy transformations is the transformation between potential energy and kinetic energy. In waterfalls such as Niagara Falls, potential energy is transformed to kinetic energy. The water at the top of the falls has gravitational potential energy. As the water plunges, its velocity increases.

Explanation:

Hope this helps you

( I got this from transformation and conservation article)

A fisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. It takes a time of 2.10 s for the boat to travel from its highest point to its lowest, a total distance of 0.600 m . The fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart.

Required:
a. How fast are the waves traveling?
b. What is the amplitude of each wave?
c. If the total vertical distance traveled by the boat were 0.30 m but the other data remained the same, how would the answers to parts (a) and (b) be affected?

Answers

Answer:

See Explanation

Explanation:

a) We know that;

v = λf

Where;

λ = wavelength of the wave

f = frequency of the wave

v = velocity of the wave

So;

T = 2 * 2.10 s = 4.2 s

Hence f = 1/4.2 s

f = 0.24 Hz

The wavelength =  6.5 m

Hence;

v = 6.5 m * 0.24 Hz

v = 1.56 m/s

b)The amplitude of the wave is;

A =  0.600 m/2 = 0.300 m

c) Since the wave speed does not depend on the amplitude of the wave then the answer in (a) above remains the same

Where d = 0.30 m

A = 0.30 m/2 = 0.15 m

which chareged particles contribute to electricity, magnetism, and light

Answers

Answer:

Explanation:charged particles create an electric force field. Moving charged particles create a magnetic force field. Accelerating charged particles produce changing electric and magnetic force fields which propagate as EM waves.

To measure the heat capacity of an object, all you usually have to do is put it in thermal contact with another object whose heat capacity you know. As an example, suppose that a chunk of metal is immersed in boiling water (100°C), then is quickly transferred into a Styrofoam cup containing 250 g of water at 20°C. After a minute or so, the temperature of the contents of the cup is 24°C. Assume that during this time no significant energy is transferred between the contents of the cup and the surroundings. The heat capacity of the cup itself is negligible.
What is the heat capacity of this chunk of metal?

Answers

Answer:

The answer is "[tex]55.05 \ \frac{J}{K}[/tex]"

Explanation:

Given value:

[tex]Q_m=4.184 \times 10^3 \ J\\T_0=100^{\circ}\\T_1=24^{\circ}[/tex]

Calculating the heat capacity of this chunk of metal:

Using formula:

[tex]C_m=\frac{Q_m}{T_0-T_1}\\[/tex]  

      [tex]=\frac{4.184 \times 10^3}{100 -24}\\\\=\frac{4.184 \times 10^3}{76}\\\\=55.05 \ \frac{J}{K}[/tex]

HELP ASAP DUE IN 5MIN

1. When a skydiver jumps out of a plane, the force that converts PE to KE is ?

2. In a fair experiment, the things that can change, causing a change in the outcome are called?

3. For a test to produce strong evidence for a claim, how many variables must be tested at a time?​

Answers

1. When the skydiver goes up in the air it storing energy ( potential energy). But when the skydiver jumps out of the plane the diver is using motion or movement to do it so is using energy ( kinetic energy)
2. It’s variables
3. Only one variables can only be tested at a time.

I hope this helps let me know if you have any questions

With no friction, you can use the relationship between potential and kinetic energy to predict the speed of the car at the bottom of this hill from its starting height.

a. True
b. False

Answers

I guess true not sure

How much heat is required to heat 2 kg of water from 25°C to 40°C?

Answers

Answer:

126000 J

Explanation:

Applying,

Q = cm(t₂-t₁).................. Equation 1

Where Q = Amount of heat, c = specifc heat capacity of water, m = mass of water, t₁ = Initial temperature, t₂ = Final temperature.

From the question,

Given: m = 2 kg, t₁ = 25°C, t₂ = 40°C

Constant: c = 4200 J/kg.°C

Substitute these value into equation 1

Q = 2×4200(40-25)

Q = 2×4200×15

Q = 126000 J

1. In order to change the speed of a wave, you must change something about the medium. T or F

2. Diffraction is the process in which waves spread out as they pass through an opening. T or F

3. The larger the opening a wave passes through, the more the wave will diffract. T or F

Answers

Answer:

1) False

As the frequency can be defined as the number of times wave formed per unit time or in other words the numbers of a combination of a crest and trough forms. So the frequncy of a sound wave depends upon the source producing sounds

2)False

Diffraction is the process in which a light wave bends when they pass through a specified medium such as water.

3)True

hope it helps

what is meant by measurementwhat are the three requirements for selecting a unit of a physical quantity ​

Answers

Answer:

Three requirements for selecting a unit are

1. The unit should be reproducible.

2. It should be possible to define the unit without ambiguity.

3. The value of the unit should not change with space and time.

At a playground a student runs at a speed of 5 m/s and jump onto a circular disk of radius 3/2 m that is free to rotate around a fixed vertical axle. The student jumps on the disk several times, and the angular speed after the student lands is measured each time. Which of the following angular speeds is not a reasonable value for the measured angular speed?

a. 0.5 rad/s
b. 1 rad/s
c. 2 rad/s
d. 3 rad/s
e. 4 rad/s

Answers

Answer:

e. 4 rad/s

Explanation:

The maximum amount of angular velocity that can be reached by the disk can be found using the following formula:

[tex]v = r\omega\\\\\omega = \frac{v}{r}[/tex]

where,

ω = maximum angular velocity = ?

v = linear speed = 5 m/s

r = radius of disc = 1.5 m

Therefore,

[tex]\omega = \frac{5\ m/s}{1.5\ m} \\\\\omega = 3.33\ rad/s[/tex]

Therefore, the angular speed can be lower than this value due to frictional losses, but it can not exceed this value in the given linear speed limit of 5 m/s.

Hence, the correct option is:

e. 4 rad/s

please select all that would be categorized as vectors

Answers

Answer:

1. 10 ft/s² straight up

2. 4 Km north-west

3. 20 m/s South

Explanation:

To successfully categorize the quantities given above as vectors, we must understand what vector quantity is.

A vector quantity is a quantity that has both magnitude and direction.

Considering the question given above, the vector quantities are:

1. 10 ft/s² straight up

2. 4 Km north-west

3. 20 m/s South

The remaining quantities in the question are not considered as vectors because they only have magnitude but no direction. They are therefore referred to as scalar quantities.

A tension of 35.0N is applied downward on a 2.50kg mass. What is the acceleration of the mass?
A. -59.5 m/s2
B. -14.0 m/s2
C. -4.20 m/s2
D. -23.8 m/s2​

Answers

Answer:

D. -23.8 m/s2​

Explanation:

Answer:

[tex]\text{B. }-14.0\:\mathrm{m/s^2}[/tex]

Explanation:

From Newton's 2nd Law, we have [tex]\Sigma F=ma[/tex].

Substituting given values, we get:

[tex]-35.0=2.50a,\\a=\frac{-35.0}{2.50},\\a=\boxed{-14.0\:\mathrm{m/s^2}}[/tex]

*Note the negative sign simply implies that the mass is travelling downwards (direction).

Science questions!! Please help!!
Post Assessment on Investigating the Immune System
please help!! Please choose the right answers!! Dont guess if you dont know the answers!!

Answers

Answer:

1. b

2. c

3. b

4. a

5. a

6. c

7. c

8. d

Which situation is contrary to Newton’s first law of motion?

An object at rest begins to move when an external force is applied.
A moving object has a constant velocity under the influence of balanced forces.
An object at rest stays at rest as long as unbalanced forces act on it.
A moving object slows down when an external force is applied.

Answers

Answer:

An object at rest stays at rest as long as unbalanced forces act on it.

Explanation:

Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.

In physics, Sir Isaac Newton's First Law of Motion is known as Law of Inertia and it states that, an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.

The inertia of a physical object such as a truck is greatly dependent or influenced by its mass; the higher the quantity of matter in a truck, the greater will be its tendency to continuously remain at rest.

Hence, the situation which is contrary to Newton’s first law of motion is that, an object at rest stays at rest as long as unbalanced forces act on it.

According to Newton’s first law of motion, an object at rest stays at rest as long as unbalanced forces do not act on it.

Answer:

yes it right

Explanation:

cat

Think about routine tasks that astronauts might need to do inside and outside a
spaceship. Choose several tasks, and describe the features the ship and spacesuits
should have to account for zero gravity as the astronaut completes the task. Use
Newton's laws of motion in your analysis..

Answers

Answer:Ok, here we go...Explanation:Astronauts perform many tasks as they orbit Earth. The space station is designed to be a permanent orbiting research facility. Its major purpose is to perform world-class science and research that only a microgravity environment can provide. The station crew spends their day working on science experiments that require their input, as well as monitoring those that are controlled from the ground. They also take part in medical experiments to determine how well their bodies are adjusting to living in microgravity for long periods of time.Working on the space station also means ensuring the maintenance and health of the orbiting platform. Crew members are constantly checking support systems and cleaning filters, updating computer equipment: doing many of the things homeowners must do to ensure their largest investment stays in good shape. Similarly, the Mission Control Center constantly monitors the space station and sends messages each day through voice or email with new instructions or plans to assist the crew members in their daily routines.

from the NASA website, COPYRIGHT Jun 8, 2015

A 190 lb man riding a 30 lb bicycle rides up a hill 60 ft high in one minute. What is the horsepower developed during this time?

Answers

the answer is c



Explanation:

what is the acceleration of each body of mass 5kg rests on a frictionless table and is connected to a cable that passes over a pulley onto a hanging body of mass 10kg​

Answers

Answer:

6.53 m/s²

Explanation:

Let m₁ = 5 kg and m₂ = 10 kg. The figure is attached and free body diagrams of the objects are also attached.

Both objects (m₁ and m₂) have the same magnitude of acceleration(a). Let g be the acceleration due to gravity = 9.8 m/s². Hence:

T = m₁a               (1)

m₂g - T = m₂a    (2)

substituting T = m₁a in equation 2:

m₂g - m₁a = m₂a

m₂a + m₁a = m₂g

a(m₁ + m₂) = m₂g

a = m₂g / (m₁ + m₂)

a = (10 kg * 9.8 m/s²) / (10 kg + 5 kg) = 6.53 m/s²

Both objects have an acceleration of 6.53 m/s²

True or False: It would be easier to run on a planet with high gravity than one with less gravity.

Answers

True! It would be easier

POSSIBLE POINTS: 4
A sound wave traveling through a solid material has a frequency of 5 hertz. The wavelength of the sound wave is 2 meters. What is the speed of sound in
the material?
50 m/s
1,000 m/s
.
25 m/s
10 m/s
17
18 19 20 21 22 23 24 25 26
19 20 21 2
Ne
12631
MAY
20
0
étv

Answers

Answer:

v = fy

speed is equal to frequency × wavelength

5 × 2

[tex]10m.s^{ - 1} [/tex]

3.6 Make innovative suggestions on how you could instill healthy environmental values
in communities.

Answers

You could hold rallies which attract a lot of people, they come and you discuss apon making the world a better place and how you want to shape the society.

An object is moving in a straight line at constant speed. A resultant torce begins to act upon
the object.
State the ways in which the force may change the motion of the object

Answers

Answer: The velocity magnitude or the velocity direction chages.

Explanation:

According to Newton's second law of motion, the acceleration of a system moved in same direction and is also directly proportional to the external force which acts on it while inversely proportional to the mass. The formula is: a = F/m

Based on the question, since the object obtains acceleration, then it can be infered that there will be changes in the velocity magnitude or the direction as a result of the motion.

1. What kind of force is the force of gravity? (1 Point) contact force
non-contact force electromagnetic force imaginary force

Answers

Answer:

the answer is electromagnetic force because gravity is a force of attraction

When two charged particles are moving toward each other, their velocities decrease until they eventually come to a
stop. What happens afterward? (1 point)
O They remain in the same place without moving.
O They accelerate toward each other.
O they bond and accelerate together.
O They accelerate in opposite directions.

Answers

Answer: 3rd option!
They bond and accelerate together

When two charged particles are moving toward each other, they bond and accelerate together.

To find the correct statement among all the options, we need to know about electromagnetic force.

What is electromagnetic force?The force between any two dynamic charged particles is the electromagnetic force. It's a combination of electric force and magnetic force. What does happen, when two charged particles move towards each other?When two charged particles move towards each other, they combine with each other dur to the electromagnetic force. Then they are travelled together as a single particle along the direction of more acceleration.

Thus, we can conclude that the option (C) is correct.

Learn more about electromagnetic force here:

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If a car has a force of 900 N and has a mass of 650 kg. What would be the acceleration of the
car as it moves down the street?

Answers

65 mph ;) your welcome

When the velocity of a body increase with time, it's acceleration is ---------

positive
negative

Answers

Answer:

Negative

Explanation:

Description of a recent example of human trafficking that has displayed in your community​

Answers

I personally never seen news about human trafficking in my community but that doesn’t mean it’s not a thing. Many ways human trafficking happens is by people getting slashed in the lower region of their legs as they walk to their car. People would hide under their car and wait until the victim is close enough to the sharp object.

If you make multiple measurements of your height, you are likely to find that the results vary by nearly half an inch in either direction due to measurement error and actual variations in height. You are slightly shorter in the evening, after gravity has compressed and reshaped your spine over the course of a day. One measurement of a man's height is 6 feet and 1 inch. Express his height in meters, using the appropriate number of significant figures.

Answers

Answer:

H = 1.85 m

Explanation:

First, we will convert the height completely into inches. 1 feet contains 12 inches in it. Therefore:

H = (6 feet)(12 inch/1 feet) + 1 inch

H = 73 inches

Now, we will convert this height from inches to meters. 1 inch is equivalent to 0.0254 m. Therefore:

H = (73 inches)(0.0254 m/1 inch)

H = 1.85 m

what is Archimedes principle?​

Answers

Archimedes' principle states that a body immersed in a fluid is subjected to an upwards force equal to the weight of the displaced fluid. This is a first condition of equilibrium. We consider that the above force, called force of buoyancy, is located in the centre of the submerged hull that we call centre of buoyancy.

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