Answer:

Explanation:
A differential equation that contain a term with di(t)/dt is in a RL circuit. Here we have

where vr is the voltage in the resistance, vi is the voltage in the inductance and vb is the source voltage. But also we have that

where L is the inductance of the circuit, r is the resistance an i is the current. By replacing we have the differential equation

I hope this is useful for you
regards
To solve the problem it is necessary to take into account the concepts related to beat frequency, i.e., The number of those wobbles per second.
The equation that describes the beat frequency is

For our given case we have that the frequency of the instrument is 440Hz and the Beat frequency is 5Hz therefore,
A) The frequency of the violin would be given by




B) <em>The violinist must loosen the string.</em> As the tightening increases the frequency, thereby increasing the number of beats from 5 to 6, i. e, on thightening the string, the frequency further increases as high frequency will be produced by short trings.
Answer: 1.57
Explanation:
This described situation is known as Refraction, a phenomenon in which light bends or changes its direction when passing through a medium with a index of refraction different from the other medium.
In this context, the index of refraction is a number that describes how fast light propagates through a medium or material.
According to Snell’s Law:
(1)
Where:
is the first medium index of refraction (the value we want to know)
is the second medium index of refraction (air)
is the angle of incidence
is the angle of refraction
Now, let's find
from (1):
(2)
Substituting the known values:
Finally:
I believe the answer is all of the above.