Answer:
a) w / k = c
, b) λ = 1,887 10⁻¹ m
, 
= 4.42 10⁻⁴ J / m³
Explanation:
a) Maxwell's equations when solved for an electromagnetic wave result in
E = E₀ cos (kx - wt)
B = B₀ cos (kx -wt)
Where k is the vector ce wave and w the angular velocity
k = 2π / λ
w = 2π f
Let's divide the two equations
w / k = f λ
w / k = c
Therefore, for w and k to be a solution to Maxwell's equations, their relationship must be equal to the speed of light.
b) If w = 10¹⁰ s⁻¹
w = 2π f
f = w / 2π
f = 10¹⁰ / 2π
f = 1.59 10⁹ Hz
The speed of light is
c = λ f
λ = c / f
λ = 3 10⁸ / 1.59 10⁹
λ = 1,887 10⁻¹ m
Energy density is
= ½ ε₀ E₀²
= ½ 8.85 10⁻¹² (10 10³)²
= 4.42 10⁻⁴ J / m³
Power is energy per unit of time
P = / t
We calculate for every second
P = 4.42 10⁻⁴ W / m³
The flow or intensity of energy is
I = S = c u
I = 3. 108 4.42 10⁻⁴
I = 1.33 10⁵ W / m2
The force on an object use Socratic glad to help ..
One crest of a wave to another.
Answer: the sun
Explanation:
The sun's radiant energy reaches the earth's surface either directly through radiation, indirectly through convection, or it can move "across" or "through" objects or materials on the surface via conduction. Let's look more closely at each case. We've probably experienced the feeling of "warmth" of the sun on our skin on a sunny day. Light energy from the sun is reaching us across space and down through the atmosphere through radiation. A dark colored vehicle in the sun quickly becomes warm (or hot!) to the touch because of radiation. The light energy from the sun heats the air in the earth's atmosphere, and this drives convection and transfers thermal energy around. It is possible that we've felt a "hot breeze" on our skin on sunny days. The thermal energy in the air will be carried to objects in its path, and it will warm them.
Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).
Explanation:
Kinetic energy of the hammer ,K.E.=
Half of the kinetic energy of the hammer is transformed into heat in the nail.
Energy transferred to the nail in one blow =
Total energy transferred after 3 blows,Q =
Mass of the nail = 15 g = 0.015 kg
Change in temperature =
Specif heat of the steel = c = 448 J/kg K
The increase in temperature of the nail after the three blows is 8.1 Kelvins.Hence, correct option is (d).
