Answer:
c.
Explanation:
Electromagnetic waves are waves that are generated when an electric field and a magnetic field vibrate together. They are usually created whenever an electric field collides with a magnetic field.
In more generic terms for an electric field, the energy per unit volume is given by:
Energy density = 
For magnetic field:
Energy density =
∴
For the electromagnetic wave (u):
Total energy density is:
Due to the fact that the energy related with both fields is equivalent:
Then:
E = cB
Answer:
Explanation:
As we know that when we increase the temperature of the rod and the ruler then in that case there will be change in the length of the both.
Due to this the ruler measurement is different from actual length of the rod
So by thermal expansion we know that
Now for length of unit division of steel scale
now the measured length from the scale is given as
Answer:
The angular frequency 
of the oscillation is 
Explanation:
For this particular situation, the angular frequency of the system is given by
Answer:
a) The voltage in an european house is 2,17 times greater than in an american House. That is 183 volts more than in US.
b) the number of cycles or oscillations for an US House is 60 cycles per second
Explanation:
To answer this this question you have to know the wave equation:
x(t) = A Sin (a + b.t)
where
x(t) = is the position as a time function... In this exercise we could call V(t) instead of x(t) beacause we want to know voltage vs time.
A = is the amplitude of the wave. In this case the maximum voltage that can be reached.
a = is the offset in time or number of waves (zero in this exercise)
b = constant that varies the frequency
then...
a) calculate the ratio between both amplitudes:
b) frequency (Oscillations) is:
b = 2pi/T = 2pi*F remember that: T = 1/F
where
F = frequency
T = Period
so for US household we have:
120pi =2pi*F
therefore
F = 120/2 = 60 Hertz
