The answer to your question is OPTION B
Question
What is the length of the pipe?
Answer:
(a) 0.52m
(b) f2=640 Hz and f3=960 Hz
(c) 352.9 Hz
Explanation:
For an open pipe, the velocity is given by
Making L the subject then
Where f is the frequency, L is the length, n is harmonic number, v is velocity
Substituting 1 for n, 320 Hz for f and 331 m/s for v then
(b)
The next two harmonics is given by
f2=2fi
f3=3fi
f2=3*320=640 Hz
f3=3*320=960 Hz
Alternatively, 
and 
(c)
When v=367 m/s then
Answer:570.54 N
Explanation:
Given
mass of man=76 kg
As man is standing over inclined building therefore
its weight has two components i.e. sin and cos component
Force perpendicular to inclined wall
F=570.54 N
Answer:
Recall the Diffraction grating formula for constructive interference of a light
y = nDλ/w Eqn 1
Where;
w = width of slit = 1/15000in =6.67x10⁻⁵in =
6.67x10⁻⁵ x 0.0254m = 1.69x10⁻⁶m
D = distance to screen
λ = wavelength of light
n = order number = 1
Given
y1 = ? from 1st order max to the central
D = 2.66 m
λ = 633 x 10-9 m
and n = 1
y₁ = 0.994m
Distance (m) from the central maximum (n = 0) is the first-order maximum (n = 1) = 0.994m
Q b. How far (m) from the central maximum (m = 0) is the second-order maximum (m = 2) observed?
w = width of slit = 1/15000in =6.67x10⁻⁵in =
6.67x10⁻⁵ x 0.0254m = 1.69x10⁻⁶m
D = distance to screen
λ = wavelength of light
n = order number = 1
Given
y1 = ? from 1st order max to the central
D = 2.66 m
λ = 633 x 10⁻⁹ m
and n = 2
y₂ = 0.994m
Distance (m) from the central maximum (n = 0) is the first-order maximum (n = 2) =1.99m
