Question

A plane progressive wave is given by $ y=25\cos (2\pi t-\pi x) $ Then the amplitude and frequency are respectively

• A. 25, 100
• B. 25, 1
• C. 25, 2
• D. 50 $ \pi , $ 2

Answer 1

Answer: (B)

Given equation is
$y=25 \cos (2 \pi t-\pi x)$ ... (1)
Standard equation is
$y=A \cos (\omega t-k x)$ ... (2)
Comparing (1) and (2),
Amplitude, $A=25, \omega=2 \pi, k=\pi$
$\therefore $ Frequency, $n=\frac{\omega}{2 \pi}$
$=\frac{2 \pi}{2 \pi}=1\, Hz$