Answer:
The first overtone frequency is 100 Hz.
Solution:
According to the question:
Length of pipe, l = 1.75 m
Speed of sound in air, v_{sa} = 350 m/s
Frequency of first overtone,
is given by:


Since, the frequency, as clear from the formula depends only on the speed
and the length. It is independent of the air temperature.
Thus there will be no effect of air temperature on the frequency.