a) 80 J
b)
c)
d) 0.091 T
Explanation:
a)
The relationship between energy and power is
where
P is the power
E is the energy delivered
t is the time elapsed
In this problem, we have:
is the average power of the pulse
is the duration of one pulse of light
Solving for E, we can find the energy given to the cell during this pulse:
However, this is the energy spread over 100 cells. So, the energy given to 1 cell is:
B)
The intensity delivered by the pulse is given by
where
P is the power of the pulse
A is the area over which the power is spread
In this problem:
is the average power of the pulse
The area is the surface area of the cell, which has the shape of a disk, so its area is given by
where
is the diameter of the cell
However, the pulse is spread over 100 cells, so the total area to consider is the area of 100 cells:
So the intensity is
And substituting we find:
c)
The relationship between power of an electromagnetic wave and maximum value of the electric field in the pulse is given by
where
is the vacuum permittivity
E is the maximum value of the electric field
is the speed of light
In this problem, we have
is the average power of the pulse
Therefore, by re-arranging the equation for E, we can find the maximum value of the electric field of the pulse.
It is:
D)
In an electromagnetic wave, the relationship between amplitude of the electric field and amplitude of the magnetic field is given by
where
E is the amplitude of the electric field
B is the amplitude of the magnetic field
c is the speed of light
Here we have:
is the amplitude of the electric field for this pulse
is the speed of light
Solving the equation for B, we find the maximum value of the magnetic field in the pulse: