Answer:
B. The frequency is greater than 1.9 Hz.
Explanation:
As we know by the equation of frequency of wave
here we know that
now from above formula we have
now it's given that when wave is travelling then temperature of the medium is heated to greater temperature.
So here energy is given by the wave to the medium so here we can say that the frequency of wave must be more than this calculated frequency as we know that this some of its energy is given to medium so that its temperature is increasing
Statement :- We assume the orthagonal sequence in Hilbert space, now
, the Fourier coefficients are given by:
Then Bessel's inequality give us:
Proof :- We assume the following equation is true
So that, is projection of
onto the surface by the first
of the
. For any event,
Now, by Pythagoras theorem:
Now, we can deduce that from the above equation that;
For , we have
Hence, Proved