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A solenoidal coil with 21 turns of wire is wound tightly around another coil with 350 turns. The inner solenoid is 22.0 cm long and has a diameter of 2.20 cm. At a certain time, the current in the inner solenoid is 0.150 A and is increasing at a rate of 1700 A/s.a. For this time, calculate the average magnetic flux through each turn of the inner solenoid.
b. For this time, calculate the mutual inductance of the two solenoids;
c. For this time, calculate the emf induced in the outer solenoid by the changing current in the inner solenoid.

Respuesta :

Answer:

(a)The average of magnetic flux trough each turns is [tex]3.63 \times 10^{-8}[/tex] wb.

(b) The magnitude of  mutual inductance of the two solenoid is [tex]1.596 \times 10^{-5}[/tex] H.

(c)The magnitude of emf induced in the outer solenoid by changing  current in the inner solenoid is 0.027132 v .

Explanation:

Given that,

The number of turns of the solenoid=N₁= 350

The diameter of the solenoid=D= 2.20 cm=0.022

The length of the solenoid is = [tex]l[/tex] = 22.0 cm=0.22 m

The second solenoid with [tex]N_2[/tex]= 21 turns which is wound around the solenoid at its center.

The current in the inner solenoid is [tex]I_1[/tex] = 0.150 A and is increasing at a rate of 1700 A/s i.e [tex]\frac{dI_1}{dt}= 1700[/tex] A/s

(a)

The formula of magnetic field of a solenoid is

[tex]B=\mu_0 nI=\frac{\mu_0 N_1I_1}{l}[/tex]

                 [tex]=\frac{(4\pi \times 10^{-7} T.m/A) (350)(0.15 \ A)}{0.220 \ m}[/tex]

                [tex]\approx 3.0 \times 10^{-4}[/tex] T

So, the magnetic flux of each turns

[tex]\phi = BA=B \pi (\frac d2)^2[/tex]

            [tex]=(3.0\times 10^{-4}\ T)\pi (\frac {0.022}{2} \ m)^2[/tex]

             [tex]=1.14 \times 10^{-7}[/tex]  wb

The average of magnetic flux trough each turns is [tex]3.63 \times 10^{-8}[/tex] wb.

(b)

Since the both coil wound tightly. So, the magnitude magnetic flux though each turns of both coils is same.

The mutual inductance of the two solenoid is

[tex]M=\frac{N_2\phi}{I_1}[/tex]

     [tex]=\frac{(21)(1.14 \times 10^{-7}\ wb)}{0.15\ A}[/tex]

    [tex]=1.596 \times 10^{-5}[/tex] H

(c)

The formula of emf is

[tex]\varepsilon =-M\frac{dI_1}{dt}[/tex]

  [tex]=-(1.596\times 10^{-5}\ H) (1700 \ A/s)[/tex]

  [tex]=27.132 \times 10^{-3}[/tex] v        

 =0.027132 v

 The emf induced in the outer solenoid by changing  current in the inner solenoid is 0.027132 v .