Answer:
the maximum intensity of an electromagnetic wave at the given frequency is 45 kW/m²
Explanation:
Given the data in the question;
To determine the maximum intensity of an electromagnetic wave, we use the formula;
= 
ε₀cE
²
where ε₀ is permittivity of free space ( 8.85 × 10⁻¹² C²/N.m² )
c is the speed of light ( 3 × 10⁸ m/s )
E is the maximum magnitude of the electric field
first we calculate the maximum magnitude of the electric field ( E )
E = 350/f kV/m
given that frequency of 60 Hz, we substitute
E = 350/60 kV/m
E = 5.83333 kV/m
E = 5.83333 kV/m × ( 
)
E = 5833.33 N/C
so we substitute all our values into the formula for intensity of an electromagnetic wave;
= ε₀cE²
= × ( 8.85 × 10⁻¹² C²/N.m² ) × ( 3 × 10⁸ m/s ) × ( 5833.33 N/C )²
= 45 × 10³ W/m²
= 45 × 10³ W/m² × ( 
)
= 45 kW/m²
Therefore, the maximum intensity of an electromagnetic wave at the given frequency is 45 kW/m²
<span>Describe the relationship of attractive forces between molecules and the ability of a solvent to dissolve a substance. Solvents can dissolve a substance only if the attraction of the solvent molecules is greater than the attraction between the molecules of the substance.</span>
Answer:
B) What is the enthalpy change, ∆H, for this reaction? Show your work to receive full credit (5 points) The enthalpy change is 150. To find it we must subtract energy of products (200) & the energy of reactants (50) so 200 – 50 equals 150.
Explanation:
B) What is the enthalpy change, ∆H, for this reaction? Show your work to receive full credit (5 points) The enthalpy change is 150. To find it we must subtract energy of products (200) & the energy of reactants (50) so 200 – 50 equals 150.
Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:
where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.
All, or almost all, warm-blooded creatures get rid of excess heat by evaporating moisture from their bodies. It's a great system, because evaporation takes a lot of heat. That's the reason people perspire when we're active and build up a lot of heat inside. The evaporation of sweat from our skin carries away heat with it.
Dogs do not sweat on their skin. The only place they can evaporate moisture is through their mouth. Panting speeds up the evaporation by blowing air across the moisture.
