An electromagnetic wave has an electric field given by
e? (y, t)=[3.90×105v/mcos(ky−(1.200×1013ra d/s)t)]k^
in which direction is the wave traveling? what is the wavelength of the wave?

λ = 157 μm

Explanation:

given,

now,

ω = 1.2 x 10¹³ rad/s

f = 1.91 x 10¹² Hz

determine the wavelength of the E M wave

   λ = 1.57 x 10⁻⁴ m

   λ = 157 x 10⁻⁶ m

   λ = 157 μm

hence, the wavelength of the wave is equal to λ = 157 μm

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.