Answer:
The relationship between the initial stored energy
and the stored energy after the dielectric is inserted
is:
c) 
Explanation:
A parallel plate capacitor with
that is connected to a voltage source
holds a charge of
. Then we disconnect the voltage source and keep the charge
constant . If we insert a dielectric of
between the plates while we keep the charge constant, we found that the potential decreases as:

The capacitance is modified as:

The stored energy without the dielectric is
The stored energy after the dielectric is inserted is:

If we replace in the above equation the values of V and C we get that


Finally

Almost anything that isn't a metal. Rubber, pure water, wood, and plastic, are all good answers.
Frequency is defined as the number of repetitions of waves occurring in 1 second. The frequency heard by the man as the ambulance move toward him will be greater than 450 Hz.
<h3>
What is the frequency ?</h3>
Frequency is defined as the number of cycles completed in 1 second. Frequency is given by the formula as,

As the formula shows frequency is inversely proportional to the time that shows if the time is decreasing frequency will increase and vice versa.
In the above case, the ambulance is moving toward the men. So that the time to meet up is decreased that's why the frequency will be greater than the initial frequency from the siren.
Hence the frequency heard by the man as the ambulance move toward him will be greater than 450 Hz.
To learn more about frequency refer to the link ;
brainly.com/question/4393505
Given:
Force(F): 100 N
Acceleration: 10 m/s^2
Now we know that
F= mx a
Where F is the force acting on the object which is measured in Newton
m is the mass of the object measured in Kg
a is the acceleration measured in m/s^2
Substituting the given values in the above formula we get
100= 10m
m= 10 Kg
A. The switch within the closed circuit is opened.
If the switch is opened current will stop flowing, as the current will meet a gap, that is not connected by a conductor.