Question

Two light waves are represented by $y_1=4\sin \omega t$ and $y_2=3\sin (\omega t+\frac{\pi }{2})$ . The resultant amplitude due to interference will be

• A. $5cm$
• B. $7cm$
• C. $1cm$
• D. $0$

Answer 1

Answer: (A)

$5cm$

The two waves are $y_1=4\sin \omega t$ and $y_2=3\cos \omega t$, the resultant wave $y=y_1+y_2$
$=4\sin \omega t+3\cos \omega t$.
The resultant amplitude $=\sqrt{4^2+3^2}$
$=\sqrt{25}=5$