<p>A piece of copper wire is formed into a single circularloop of radius 11 cm. A magnetic field is oriented parallel to thenormal to the loop, and it increases from 0 to 0.74 T in a time of0.60 s. The wire has a resistance per unit length of 2.5 x 10-2 /m.What is the average electrical energy dissipated in the resistanceof the wire?<br /><br />I know the answer is0.076325579950 J But I don't know how to get it. <br /><br/>My professor told us to do the following:<br />emf=ΔΦ/Δt = [(BA)(final)- (BA)(initial)]/Δt                             A=pi*r^2<br />emf= [(.74*pi*.11^2)-(0*pi*.11^2)]/.60=.04688volts<br />Resistance=2.5x10^-2(2*pi*r)=2.5x10^-2(2*pi*.11)=.1728<br />P=emf^2/R=.04688^2/.1728= .012718Watts</p>
<p>This obviously isn't giving me the right anwer. Could youplease show me the proper method? Thanks!</p>
<p>A piece of copper wire is formed into a single circularloop of radius 11 cm. A magnetic field is oriented parallel to thenormal to the loop, and it increases from 0 to 0.74 T in a time of0.60 s. The wire has a resistance per unit length of 2.5 x 10-2 /m.What is the average electrical energy dissipated in the resistanceof the wire?<br /><br />I know the answer is0.076325579950 J But I don't know how to get it. <br /><br/>My professor told us to do the following:<br />emf=ΔΦ/Δt = [(BA)(final)- (BA)(initial)]/Δt                             A=pi*r^2<br />emf= [(.74*pi*.11^2)-(0*pi*.11^2)]/.60=.04688volts<br />Resistance=2.5x10^-2(2*pi*r)=2.5x10^-2(2*pi*.11)=.1728<br />P=emf^2/R=.04688^2/.1728= .012718Watts</p>
<p>This obviously isn't giving me the right anwer. Could youplease show me the proper method? Thanks!</p>
