Are torsional waves longitudinal or transverse?

The speed of radio-waves in vacuum is $3\times {10}^8 \mathrm{m}/\mathrm{s}$. Find the wavelength for

(i) An AM radio station with frequency $100 \mathrm{kHz}$

(ii) An FM radio station with frequency $100 \mathrm{MHz}$.

The equation of a certain progressive wave is $y=2 \sin 2\pi \left(\frac{t}{0.01}-\frac{x}{30}\right)$ where $x$ and $y$ are in centimetre and $t$ is seconds. What are

Speed of propagation.

The equation of a wave travelling on a string stretched along $x$ - axis is given by
$\mathrm{y}={\mathrm{Ae}}^{-{\left(\frac{\mathrm{s}}{\mathrm{a}}-\frac{\mathrm{t}}{\mathrm{T}}\right)}^2}$

(a) Write the dimension of $\mathrm{A}, \mathrm{a}$ and $\mathrm{T}$

(b) Find the wave speed

(c) In which direction the wave is travelling?

(d) Where is the maximum pulse located at $\mathrm{t}=\mathrm{T}$? at $\mathrm{t}=2\mathrm{T}$ ?

The displacement of the particle at $\mathrm{x}=0$ of a stretched string carrying a wave in the positive $x$ -direction is given by $\mathrm{f}\left(\mathrm{t}\right)=\mathrm{Asin}\left(\raisebox{1ex}{$\mathrm{t}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{T}$}\right.\right)$. The wave speed is $\vartheta$. Write the wave equation.

Write down the equation to a wave travelling in negative $\mathrm{x}$ -direction and having amplitude $0.01 \mathrm{m}$, frequency $550\mathrm{Hz}$, and a speed $330 \mathrm{m}/\mathrm{s}$.