Answer:
0.786 Hz, 1.572 Hz, 2.358 Hz, 3.144 Hz
Explanation:
The fundamental frequency of a standing wave on a string is given by

where
L is the length of the string
T is the tension in the string
is the mass per unit length
For the string in the problem,
L = 30.0 m

T = 20.0 N
Substituting into the equation, we find the fundamental frequency:

The next frequencies (harmonics) are given by

with n being an integer number and f being the fundamental frequency.
So we get:



D. They are heterotrophs that digest food internally.
You're fishing for "polarization".
Complete Question
The complete question is shown on the first uploaded image
Answer:
The maximum emf is 
The emf induced at t = 1.00 s is 
The maximum rate of change of magnetic flux is 
Explanation:
From the question we are told that
The number of turns is N = 44 turns
The length of the coil is 
The width of the coil is 
The magnetic field is 
The angular speed is 
Generally the induced emf is mathematically represented as

Where
is the maximum induced emf and this is mathematically represented as

Where
is the magnetic flux
N is the number of turns
A is the area of the coil which is mathematically evaluated as

Substituting values


substituting values into the equation for maximum induced emf


given that the time t = 1.0sec
substituting values into the equation for induced emf 


The maximum induced emf can also be represented mathematically as

Where
is the magnetic flux and
is the maximum rate at which magnetic flux changes the value of the maximum rate of change of magnetic flux is

The sound is perceived as louder if the amplitude increases, and softer if the amplitude decreases. ( for amplitude)
Since sound at all frequencies has the same speed in air, a change in frequency means a change in wavelength. ( for frequency)