Question

Consider the superposition of N harmonic waves of equal amplitude and frequency. If N is a very large number determine the resultant intensity in terms of the intensity $\left(I_0\right)$ of each component wave for the condition when the component waves have identical phases.

• A. ${NI}_0$
• B. $N^2{I}_0$
• C. $\sqrt{N}{I}_0$
• D. $I_0$

Answer 1

The correct option is A ${NI}_0$

As all the waves are in phase and having same amplitude and frequency

So, the intensities will simply get add to give the resultant intensity

$\Rightarrow (Intensity{)}_{Resultant}=(I_0+I_0+.....I_0)-Ntimes=N{I}_0$