 51
 2
 Homework Statement
 Find the loops resistance
 Homework Equations
 N/A
Question:
In Figure (a), a circular loop of wire is concentric with a solenoid and lies in a plane perpendicular to the solenoid's central axis.The loop has radius 6.13 cm. The solenoid has radius 2.07 cm, consists of 8230 turns/m, and has a current i_sol varying with time t as given in Figure (b), where the vertical axis scale is set by i_s = 1.03 A and the horizontal axis scale is set by ts = 4.6 s. Figure (c) shows, as a function of time, the energy E that is transferred to thermal energy of the loop; the vertical axis scale is set by Es = 101.6 nJ. What is the loop's resistance?
I want to find B, the magnetic flux density such that I can work out what the EMF is.
From the EMF I can use
$$ P = \frac{EMF^2}{R} $$
To work out R as I know what P is since that is J/s.
However how can I find B when:
$$ B = \frac{\mu N I}{2R}$$
and I don't know what the current (I) is? As the current varies over time.
If someone could provide what is going on in terms of the physics and the required next steps that would be great!
In Figure (a), a circular loop of wire is concentric with a solenoid and lies in a plane perpendicular to the solenoid's central axis.The loop has radius 6.13 cm. The solenoid has radius 2.07 cm, consists of 8230 turns/m, and has a current i_sol varying with time t as given in Figure (b), where the vertical axis scale is set by i_s = 1.03 A and the horizontal axis scale is set by ts = 4.6 s. Figure (c) shows, as a function of time, the energy E that is transferred to thermal energy of the loop; the vertical axis scale is set by Es = 101.6 nJ. What is the loop's resistance?
I want to find B, the magnetic flux density such that I can work out what the EMF is.
From the EMF I can use
$$ P = \frac{EMF^2}{R} $$
To work out R as I know what P is since that is J/s.
However how can I find B when:
$$ B = \frac{\mu N I}{2R}$$
and I don't know what the current (I) is? As the current varies over time.
If someone could provide what is going on in terms of the physics and the required next steps that would be great!
Attachments

4 KB Views: 13