Question

n identical waves each of intensity $1_0$ interfere with each other. The ratio of maximum intensities if the interference is (i) coherent and (ii) incoherent is:

• A. $n^2$
• B. $\frac{1}{n}$
• C. $\frac{1}{n^2}$
• D. n

Answer 1

Answer: (D)

n

In case of coherent source

$l_{max}={(\sqrt{l_0}+\sqrt{l_0}+\sqrt{l_0}+.....uptontimes)}^2=n^2{l}_0$

In case of incoherent source,

$l_{max}=n{l}_o$

$\therefore$ Ratio=n