Pls answer this ,today is last day of classes then I got finals soon lol
1 answer:
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Answer:
Option d and e are correct.
Explanation:
The expression for velocity of pulse in a stretched string can be given as follows
v =
where T is tension in the string , m is mass of string per unit length.
Use of lighter string of the same length, under the same tension amounts to higher m so velocity will decrease. Hence option d is correct.
Similarly, v is directly proportional to square root of tension. So if we increase tension , velocity also increases. So option e ) is correct.
The concept required to solve this problem is related to thin film interference.
The path length difference between two waves one is reflected from top surface of the film and the bottom surface of the film is equal to twice the thickness of the film:
Where,
Path length difference
t = thickness
At the same time we have that the constructive interference condition for a thin film interference for strongly reflected rays is
Where
Path length difference
wavelength
m = Any integer (order of the equation) which represent the number of repetition of the spectrum
Equation both expression we have
Re-arrange to find the thickness we have
Our values are given as
m = 1
= 597nm
n = 1.38
Replacing,
Therefore the thinnest thickness of the film is 216.3nm