Scientists are working on a new technique to kill cancer cells by zapping them with ultrahigh-energy (in the range of 1012 w) pulses of electromagnetic waves that last for an extremely short time (a few nanoseconds). these short pulses scramble the interior of a cell without causing it to explode, as long pulses would do. we can model a typical such cell as a disk 4.0 μm in diameter, with the pulse lasting for 5.0 ns with an average power of 1.59×1012 w . we shall assume that the energy is spread uniformly over the faces of 100 cells for each pulse. a. how much energy is given to the cell during this pulse? u=. what is the intensity (in w/m^2) delivered tothe cell? i=/m^2c. what is the maximum value of the electric field in the pulse? emax=/md. what is the maximum value of the magnetic field in the pulse? bmax=

1.

The total energy given to the cells during one pulse is given by:

where

P is the average power of the pulse

t is the duration of the pulse

In this problem,

Substituting,

2.

The energy found at point (1) is the energy delivered to 100 cells. The radius of each cell is

So the area of each cell is

The energy is spread over 100 cells, so the total area of the cells is

And so the intensity delivered is

3.

The average intensity of an electromagnetic wave is related to the maximum value of the electric field by

where

c is the speed of light

is the vacuum permittivity

E is the amplitude of the electric field

Solving the formula for E, we find:

4. 3247 T

The magnetic field amplitude is related to the electric field amplitude by

where

E is the electric field amplitude

c is the speed of light

B is the magnetic field

Solving the equation for B and substituting the value of E that we found at point 3, we find

wire in brush may conduct electricity from cell to drill and vice versa electrc shock possible