1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
erik [133]
3 years ago
14

The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.724 W/m^2. What is the maximum v

alue of the magnetic field in the wave?
a. 77.9 nT
b. 55.1 nT
c. 38.9 nT
d. 108 nT
Physics
2 answers:
alexira [117]3 years ago
8 0

Answer:

a. 77.9 nT

Explanation:

Given;

average value of the electromagnetic wave, E = 0.724 W/m^2

The average value of a Poynting vector is given by;

S = \frac{1}{2\mu_o} *E_oB_o\\\\But, E_o = cB_o\\\\S = \frac{1}{2\mu_o} *cB_o^2\\\\cB_o ^2= 2\mu_o S\\\\B_o^2 = \frac{2\mu_o S}{c}\\\\B_o = \sqrt{ \frac{2\mu_o S}{c}} \\\\B_o =   \sqrt{ \frac{2(4\pi*10^{-7}) (0.724)}{3*10^8}}\\\\B_o = 7.79*10^{-8} \ T\\\\B_o = 77.9*10^{-9} \ T\\\\B_o = 77.9 \ nT

Therefore, the maximum value of the magnetic field in the wave is 77.9 nT.

Gala2k [10]3 years ago
5 0

Answer:

A I think : )

Explanation:

You might be interested in
Sandy is whirling a ball attached to a string in a horizontal circle over his head. If Sandy doubles the speed of the ball, what
jeka57 [31]

The tension in the string B) It quadruples.

Explanation:

The ball is in uniform circular motion in a horizontal circle, so the tension in the string is providing the centripetal force that keeps the ball in circular motion. So we can write:

T= m\frac{v^2}{r}

where:

T is the tension in the string

m is the mass of the ball

v is the speed of the ball

r is the radius of the circle (the lenght of the string)

In this problem, we are told that the speed of the ball is doubled, so

v' = 2v

Substituting into the previous equation, we find the new tension in the string:

T' = m \frac{(2v)^2}{r}=4(m\frac{v^2}{r})=4T

Therefore, the tension in the string will quadruple.

Learn more about circular motion:

brainly.com/question/2562955

brainly.com/question/6372960

#LearnwithBrainly

6 0
3 years ago
A train, traveling at a constant speed of 25.8 m/s, comes to an incline with a constant slope. While going up the incline, the t
zhannawk [14.2K]

The final velocity of the train after 8.3 s on the incline will be 12.022 m/s.

Answer:

Explanation:

So in this problem, the initial speed of the train is at 25.8 m/s before it comes to incline with constant slope. So the acceleration or the rate of change in velocity while moving on the incline is given as 1.66 m/s². So the final velocity need to be found after a time period of 8.3 s. According to the first equation of motion, v = u +at.

So we know the values for parameters u,a and t. Since, the train slows down on the slope, so the acceleration value will have negative sign with the magnitude of acceleration. Then

v = 25.8 + (-1.66×8.3)

v =12.022 m/s.

So the final velocity of the train after 8.3 s on the incline will be 12.022 m/s.

8 0
3 years ago
Calculate Speed The 2-kg metal ball moving at a speed of 3 m/s strikes a 1-kg wooden ball that is at rest. After the collision,
enot [183]

Answer:

53466kg.

Explanatiokn:

5 0
2 years ago
a battery of 5v and internal resistance of 5 ohms is connected to a resistor of 20 ohms. calculate the value of terminal voltage
Alborosie

Answer:

A bird flies 75m in 15s.Calculate its speed

7 0
2 years ago
Why is everything spinning? Moons, planets and stars all rotate on their axes, moons orbit planets, planets orbit stars, spiral
kow [346]

Answer:

Conservation of angular momentum

Explanation:

When the objects spread in universe after big bang, because of the tremendous force , they gained angular momentum and started to rotate. Since, then the object continue to rotate on their axis because of conservation of angular momentum. In vacuum of space there no other forces that can stop these rotation, therefore, they continue to rotate.  

4 0
3 years ago
Other questions:
  • HELP PLEASE !!
    10·1 answer
  • What happens to the equilibrium price and quantity for jelly when the price of peanut butter increases? (Assume that peanut butt
    9·1 answer
  • If you toss a stick into the air, it appears to wobble all over the place. specifically, about what place does it wobble?
    9·1 answer
  • What is the value of work done on an object when a 0.1x102-newton force moves it 30 meters and the angle between the force and t
    12·1 answer
  • How come that there is a presence of cos there?
    8·1 answer
  • How long does it take to freeze ice cubes?
    5·1 answer
  • A centimeter in milimetersr difiers from each other by a fact of 100 ,1000, 1 or 10
    14·1 answer
  • When the Moon orbits Earth, what is the centripetal force?
    8·1 answer
  • To understand the meaning of the variables that appear in the equations for rotational kinematics with constant angular accelera
    8·1 answer
  • While in Earth's orbit, an 80-kg astronaut carrying a 20-kg tool kit is initially drifting toward a stationary space shuttle at
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!