A heat engine is a device that uses heat to produce useful work.
The outer surface of the glass expands faster than the inside surface since glass is a fairly good thermal insulator. The outer surface tries to expand without the inner surface doing so at the same time. This is the secret of Pyrex glass. It is more conductive to heat and the inner and outer surface expand (and contract) at the same time.
Answer:
f = 2858.33 Hz
Explanation:
given,
distance between speaker (A) and the person = 2.34 m
Distance between speaker (B) and the person is AB =
=
= 2.46 m
path difference d = BP - AP
= 2.46 - 2.34 m
= 0.12 m
now, λ = 0.12
speed of sound = 343 m/s


f = 2858.33 Hz
the lowest frequency that will produce constructive interference is equal to
f = 2858.33 Hz