A coil of wire is connected to an uncharged capacitor in a magnetic field

However, using the given information and equations, we can calculate the voltage across the capacitor. In summary, a coil of wire with 10 turns and a resistance of 0.20 ohms is in a 1.0 mT magnetic field. The coil is connected to an uncharged 1.0 microFarad capacitor and quickly pulled out of the magnetic field. Using the equation V = Q/C, we can calculate the voltage across the capacitor to be 7.85 x 10^-4 V.
  • #1
ANON
3
0
a coil of wire is connected to an uncharged capacitor in a magnetic field...

Homework Statement


A 10-turn coil of wire having a diameter of 1.0 cm and a resistance of 0.20 ohms is in a 1.0 mT magnetic field
with the coil oriented for maximum flux. The coil is connected to an uncharged 1.0 microFarad capacitor rather than to a current meter. The coil is quickly pulled out of the magnetic field. Afterward, what is the voltage across the capacitor?
Hint: Use I=dq/dt to relate the net change of flux to the amount of charge that flows to the capacitor.


Homework Equations


potential difference = -L dI/dt, where L is the inductance
magnetic field, B = Uo NI/l
total magnetic flux = N (magnetic field for each turn) = N (Area)(B) = (Uo N^2 A I) / l
I = V/R
induced emf = |change in magnetic flux/change in time|
V = Q/C

The Attempt at a Solution


Voltage across the capacitor initially is 0 V, since capacitor is uncharged.
I found the total flux to be 7.85 x 10^-7 Wb.
The changing flux induces an emf.

I'm really stuck here. Can someone please help me? Thanks :)
 
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  • #2
ANON said:

Homework Statement


A 10-turn coil of wire having a diameter of 1.0 cm and a resistance of 0.20 ohms is in a 1.0 mT magnetic field
with the coil oriented for maximum flux. The coil is connected to an uncharged 1.0 microFarad capacitor rather than to a current meter. The coil is quickly pulled out of the magnetic field. Afterward, what is the voltage across the capacitor?
Hint: Use I=dq/dt to relate the net change of flux to the amount of charge that flows to the capacitor.

Homework Equations


potential difference = -L dI/dt, where L is the inductance
magnetic field, B = Uo NI/l
total magnetic flux = N (magnetic field for each turn) = N (Area)(B) = (Uo N^2 A I) / l
I = V/R
induced emf = |change in magnetic flux/change in time|
V = Q/C

The Attempt at a Solution


Voltage across the capacitor initially is 0 V, since capacitor is uncharged.
I found the total flux to be 7.85 x 10^-7 Wb.
The changing flux induces an emf.

I'm really stuck here. Can someone please help me? Thanks :)
no time is given? if you're given a time then you have [tex]\frac{d\phi _B}{dt}[/tex] and a voltage
 
  • #3
No time is given.
 

1. What happens when a coil of wire is connected to an uncharged capacitor in a magnetic field?

When a coil of wire is connected to an uncharged capacitor in a magnetic field, an electric current is induced in the coil. This is because the magnetic field causes a change in the magnetic flux through the coil, which in turn generates an electric field. The electric field causes charges to flow through the wire, creating an electric current.

2. How does the magnetic field affect the induced current in the coil?

The strength of the magnetic field directly affects the magnitude of the induced current. A stronger magnetic field will induce a larger current in the coil, while a weaker magnetic field will induce a smaller current.

3. What is the role of the uncharged capacitor in this setup?

The uncharged capacitor acts as a storage device for the induced current. As the current flows through the coil, it charges the capacitor. Once the capacitor is fully charged, the current will stop flowing.

4. What happens if the magnetic field is removed while the current is still flowing?

If the magnetic field is removed while the current is still flowing, the magnetic flux through the coil will decrease. This decrease in flux will induce an opposing current in the coil, causing the current to gradually decrease until it reaches zero.

5. How does the direction of the magnetic field affect the direction of the induced current?

The direction of the induced current is determined by the direction of the magnetic field. If the magnetic field is pointing towards the coil, the induced current will flow in one direction. If the magnetic field is pointing away from the coil, the induced current will flow in the opposite direction.

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