Answer
given,
wavelength (λ)= 500 n m
thickness of film= 10⁻⁴ cm
refractive index = μ = 1.375
distance traveled is double which is equal to 2 x 10⁻⁴ cm
a) Number of wave


N = 2.91
N = 3
b) phase difference is equal to
Reflection from the first surface has a 180° (½λ) phase change.
There is no phase change for the 2nd surface reflection and there is no phase difference for the 2nd wave having traveled an exact whole number of waves.
net phase difference = 
= 270°
Answer:
Check the explanation
Explanation:
A) 7th Harmonic. (Of an open ended pipe, odd harmonics are allowed (3rd overtone))
b) f = n v / 4 L
n = 7
f = 7 x 350 / 4 x 0.41 = 1493.9 Hz
c) Let level of water H, If reduces the effective length of pipe
Using, f = n v / 4 Leff
n = 1
251.8 = 1 x 350 / 4 ( 0.41 - H)
H = 0.0625m
H = 6.25 cm
It will use a lot more energy (electricity) to cool down the room. Because heat energy from outside the room can easily transfer into the room again if the room is not well insulated. So more energy is needed to cool down the room again
Answer:It’s 5 I believe
Explanation: it says to round to the nearest thousandths, so it’ll be 5.
Which is a substance that takes the shape and volume of its container?
liquid