I'm not from that school but I can help you.
Answer:
Solution
λ=v/n
Here, v=344 m s−1
n=22 MHz =22×106 Hz
λ=344/22×106=15.64×10−6m=15.64μm.
V (speed) = F (frequency) x Wavelength
If we rearrange the formula, making frequency the subject;
F (frequency) = Speed ÷ Wavelength
F = 300,000 m\s x 4.5 e -10m
F = 0.08810409956 Hz
no, work is = force * distance or displacement