(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The magnetic field at one place on the earth’s surface is 55 μT in strength and tilted 60°

down from horizontal. A 200-turn coil having a diameter of 4.0 cm and a resistance of 2.0 Ω

is connected to a 1.0 μF capacitor rather than to a current meter. The coil is held in a

horizontal plane and the capacitor is discharged. The coil is then quickly rotated 180° so that

the side that had been facing up is now facing down. Afterward, what is the voltage across

the capacitor? [Hint: use I=dq/dt

2. Relevant equations

[tex]\Phi[/tex]=ABcos[tex]\theta[/tex]

Vc=Q/C

Vl=-L(di/dt)

Vc=-Vl

I=[tex]\Phi[/tex]/L

[tex]\Phi[/tex]=N[tex]\Phi[/tex]per coil

3. The attempt at a solution

ok wat i did was find flux per coil=[tex]\pi[/tex]r^{2}Bcos[tex]\theta[/tex]=3.45x10^{-8}

then flux=3.45x10^{-8}*200=6.9x10^{-6}=L(di/dt)=Q/C....

but that cant be right coz i know the answer is 12V... can someone please help me, ive been on this for 4 or hours and its 3am almost... due in tomoz... plz someone help...

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Inductance, flux, capacitance

**Physics Forums | Science Articles, Homework Help, Discussion**