Imax (Im) intensity is averaged over the _________.

Imax (Im) intensity is averaged over the _________.

• A. The entire cycle
• B. Most intense half-cycle
• C. Least intense half-cycle
• D. Pulse duration

Answer: (B)

The concept being tested is that the energy delivered by a pulsed or alternating wave is not constant over a cycle, so the maximum intensity is defined by averaging during the portion of the cycle where the energy is highest. Imax represents the average intensity over the half-cycle that carries the peak energy. Since intensity is proportional to the square of the instantaneous amplitude, the energy peaks around the center of the high-energy half-cycle. If you averaged over the entire cycle, you would dilute that peak with the lower-intensity portions, and if you averaged over the least intense half-cycle you’d miss the actual peak altogether. The pulse duration is a timing measure, not the interval used to define the maximum intensity. So, the most intense half-cycle is the correct interval for determining Im.

The concept being tested is that the energy delivered by a pulsed or alternating wave is not constant over a cycle, so the maximum intensity is defined by averaging during the portion of the cycle where the energy is highest.

Imax represents the average intensity over the half-cycle that carries the peak energy. Since intensity is proportional to the square of the instantaneous amplitude, the energy peaks around the center of the high-energy half-cycle. If you averaged over the entire cycle, you would dilute that peak with the lower-intensity portions, and if you averaged over the least intense half-cycle you’d miss the actual peak altogether. The pulse duration is a timing measure, not the interval used to define the maximum intensity.

So, the most intense half-cycle is the correct interval for determining Im.