An oscillating LC circuit consisting of a 1.0 nF capacitor and a 2.4 mH coil has a maximum voltage of 2.5 V. What are (a) the maximum charge on the capacitor, (b) the maximum current through the circuit, (c) the maximum energy stored in the magnetic field of the coil

Respuesta :

Answer:

[tex]2.5\times 10^{-9}\ C[/tex]

0.00161 A

[tex]3.125\times 10^{-9}\ J[/tex]

Explanation:

C = Capacitance = 1 nF

L = Inductance = 2.4 mH

[tex]V_m[/tex] = V = Voltage = 2.5 V

I = Current

Maximum charge in capacitor is given by

[tex]Q_m=CV_m\\\Rightarrow Q_m=1\times 10^{-9}\times 2.5\\\Rightarrow Q_m=2.5\times 10^{-9}\ C[/tex]

The maximum charge on the capacitor is [tex]2.5\times 10^{-9}\ C[/tex]

Energy stored in capacitor is given by

[tex]U=\frac{1}{2}CV^2\\\Rightarrow U=\frac{1}{2}\times 1\times 10^{-9}\times 2.5^2\\\Rightarrow U=3.125\times 10^{-9}\ J[/tex]

The maximum energy stored in the magnetic field of the coil is [tex]3.125\times 10^{-9}\ Joules[/tex]

Energy stored in coil is given by

[tex]U=\frac{1}{2}LI^2\\\Rightarrow I=\sqrt{\frac{2U}{L}}\\\Rightarrow I=\sqrt{\frac{2\times 3.125\times 10^{-9}}{2.4\times 10^{-3}}}\\\Rightarrow I=0.00161\ A[/tex]

The current passing through the circuit is 0.00161 A

Answer:

a. [tex]q_m=2.5\times 10^{-6}\ C[/tex]

b. [tex]i_m=5.1\times 10^{-2}\ A[/tex]

c. [tex]U_B=3.1212\times 10^{-6}\ J[/tex]

Explanation:

Given:

  • capacitance, [tex]C=10^{-6}\ F[/tex]
  • maximum voltage, [tex]V_m=2.5\ V[/tex]
  • inductance, [tex]L=2.4\times 10^{-3} \ H[/tex]

(a)

maximum charge on the capacitor:

[tex]q_m=C.V_m[/tex]

[tex]q_m=10^{-6}\times 2.5[/tex]

[tex]q_m=2.5\times 10^{-6}\ C[/tex]

(b)

∵Energy store in electric and magnetic fields are equal:

[tex]\therefore U_E=U_B[/tex]

[tex]\frac{1}{2} \times \frac{q_m}{C} =\frac{1}{2}\times L.i_m^2[/tex]

[tex]i_m=\frac{q_m}{\sqrt{L.C} }[/tex]

[tex]i_m=\frac{2.5\times 10^{-6}}{\sqrt{2.4\times 10^{-3}\times 10^{-6}} }[/tex]

[tex]i_m=5.1\times 10^{-2}\ A[/tex]

(c)

The maximum energy stored in the magnetic field of the coil:

[tex]U_B=\frac{1}{2}\times L.i_m^2 [/tex]

[tex]U_B=\frac{1}{2}\times 2.4\times 10^{-3}\times (5.1\times 10^{-2})^2[/tex]

[tex]U_B=3.1212\times 10^{-6}\ J[/tex]