An 800-khz radio signal is detected at a point 8.5 km distant from a transmitter tower. the electric field amplitude of the signal at that point is 0.90 v/m. assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. what is the average electromagnetic energy density at that point? (c = 3.0 x 108 m/s, μ0 = 4π × 10-7 t ∙ m/a, ε0 = 8.85 × 10-12 c2/n ∙ m2)

a. 7.2 pj/m3
b. 10 pj/m3
c. 3.6 pj/m3
d. 14 pj/m3
e. 5.1 pj/m3

To solve this problem we need to apply the concepts related to the average electromagnetic energy density. Which is given as

Where,

\epsilon_0 = Permettivity of free space constant

E = Electric Field amplitude

Since the average electromagnetic energy density is directly proportional to the amplitude of the magnetic field then we have to

Therefore the correct answer is C.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table