Question

A.Which figure shows the loop that the must beused as the Ampèrean loop for finding $B_z(r)$ for inside the solenoid?B.Find $B_z(r)$ , the z component ofthe magnetic field insidethe solenoid where Ampère's law applies.Express your answer in terms of,,,,and physical constants such as $mu_0$ .C.The magnetic field inside a solenoidcan be found exactly using Ampère's law only if thesolenoid is infinitely long. Otherwise, the Biot-Savartlaw must beused to find an exact answer. In practice, the field can bedetermined with very little error by using Ampère's law, aslong as certainconditions hold that make the field similar to thatin an infinitely long solenoid.

Which of the following conditions musthold to allow you to use Ampère's law to find a goodapproximation?

1. Consider only locations where the distance from the ends ismany times .
2. Consider any location inside the solenoid, as long asis much larger than for the solenoid.
3. Consider only locations along the axis of the solenoid.

Answer?

aonly bonly conly a andb a andc b andc

Answer 1

Part A: "b" is the correct answerPart B:Assumethat loop B (in the Part A figure) has length $Z_L$ along $z_unit$ . What is the loop integral in Ampère'slaw? Assumethat the top end of the loop is very far from the solenoid (eventhough it may not look like it in thefigure), so that the fieldthere is assumed to be small and can be ignored.Expressyour answer in terms of $B_z(r)$ , $Z_L$ , and other quantities given intheintroduction.= $B_{z}$ Part Ca only