Answer:
(a) T = 2987.6 k
(b) T = 19986.2 k
Explanation:
The temperature of a star in terms of peak wavelength can be given by Wein's Displacement Law, which is as follows:

where,
T = Radiated surface temperature
= peak wavelength
(a)
here,
= 970 nm = 9.7 x 10⁻⁷ m
Therefore,

<u>T = 2987.6 k</u>
(b)
here,
= 145 nm = 1.45 x 10⁻⁷ m
Therefore,

<u>T = 19986.2 k</u>
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>