Explanation:
It is given that,
Frequency of monochromatic light, 
Separation between slits, 
(a) The condition for maxima is given by :

For third maxima,



(b) For second dark fringe, n = 2





Hence, this is the required solution.
Answer:
The velocity of the wave is 12.5 m/s
Explanation:
The given parameters are;
he frequency of the tuning fork, f = 250 Hz
The distance between successive crests of the wave formed, λ = 5 cm = 0.05 m
The velocity of a wave, v = f × λ
Where;
f = The frequency of the wave
λ = The wavelength of the wave - The distance between crests =
Substituting the known values gives;
v = 250 Hz × 0.05 m = 12.5 m/s
The velocity of the wave, v = 12.5 m/s.
Answer:
ϟ 
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Hope I helped ! ッ
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