ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: naved_s9994 on July 20, 2009, 08:52:40 pm

Title: Question
Post by: naved_s9994 on July 20, 2009, 08:52:40 pm: A bar magnet is made to sping with frequency of 5.0Hz in front of copper wire. The coil has resistance of 0.25 Ohms
and consists of 20 turns each with area 10cm^2. The magnetic field strength of the magnet when it is pointed towards the
coil is 0.020 T

a) calculate the avg induced voltage in the solenoid.
b) calculate the avg induced current flow in this time

??

________________________

Also, is any one familiar with the diagram attached, to explain it?
Title: Re: Question
Post by: TrueTears on July 20, 2009, 08:57:53 pm: a) Average emf $= \frac{-N\Delta \phi}{\Delta t}$

$\phi = BA = 0.02 \times \frac{1}{1000} = \frac{0.02}{1000}$ Wb

$N = 20$

$f = \frac{1}{T}$

$5 = \frac{1}{T}$

$T = \frac{1}{5}$

Sub those in.

b) Well V = IR

You know V from a) and R from question sub in and work out I.
Title: Re: Question
Post by: naved_s9994 on July 20, 2009, 09:43:32 pm: ahh right!
yea, i stuffed the conversion from cm^2 to m^2