Sound needs medium to travel and it can not travel without medium
so sound wave is a travelling wave
now we also know that sound wave propagate in form of rarefaction and compression.
So all medium particles travel in the direction of wave only
so it is a longitudinal wave also
so correct answer will be
<em>mechanical longitudinal </em>
Answer:
94
Explanation:
f = 2.57 x 10^13 Hz
E = 10 eV = 10 x 1.6 x 10^-19 J = 1.6 x 10^-18 J
Energy of each photon = h f
Where, h is Plank's constant
Energy of each photon = 6.63 x 10^-34 x 2.57 x 10^13 = 1.7 x 10^-20 J
Number of photons = Total energy / energy of one photon
N = (1.6 x 10^-18) / (1.7 x 10^-20) = 94.11 = 94
