At some instant and location, the electric field associated with an electromagnetic wave in vacuum has the strength 57.5 V/m. Find the magnetic field strength B , the total energy density u , and the power flow per unit area, all at the same instant and location.

Explanation:

= Permittivity of free space =

= Vacuum permeability =

E = Electric field = 57.5 V/m

c = Speed of light =

Magnetic field is given by

The magnetic field strength is

Energy density is given by

The energy density is

Power flow per unit area is given by

Power flow per unit area is

they are non-matter

explanation:

they are non-matter. basically, any type of energy or any abstract concept is an example of something that does not matter. other examples include dreams, magnetism, radio, and hate

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.