Question

You put a sheet of paper in the path of a certain microwave traveling in empty space, and measure the em intensity on it over a short time interval at two different times. At the earlier observation, you observed nine times the average intensity that you do at the later observation. The peak value of the incoming electric field at the later observation must be

a. roughly equal to that at the earlier observation.

b. Impossible to answer without knowing the sheet\'s area.

c. roughly three times that at the earlier observation.

d. twice the wavelength, equal amplitude, and equal speed of propagation.

e. roughly 81 times that at the earlier observation.

Answer 1

since Intensity is directly proportional to the amplitude squired. so the amplitude i.e. the peak value is proportional to the square root of the intensity. so the correct answer should be c.