Eðlisfræði 2, vor 2007
Eðlisfræði 2, vor 2007
Eðlisfræði 2, vor 2007
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http://session.masteringphysics.com/myct<br />
04/19/<strong>2007</strong> 05:02 PM<br />
ANSWER: greater than less than equal to cannot be determined<br />
Decay of Current in an L-R Circuit<br />
Learning Goal: To understand the mathematics of current decay in an L-R circuit<br />
A DC voltage source is connected to a resistor of resistance and an inductor with inductance , forming the circuit shown in the<br />
figure. For a long time before , the switch has been in the position shown, so that a current has been built up in the circuit by<br />
the voltage source. At the switch is thrown to remove the voltage source from the circuit. This problem concerns the behavior of<br />
the current through the inductor and the voltage across the inductor at time after .<br />
Part A<br />
After , what happens to the voltage across the inductor and the current through the inductor relative to their values prior to ?<br />
Part A.1<br />
ANSWER:<br />
What is the relation between current and voltage for the inductor?<br />
Answer not displayed<br />
Part not displayed<br />
Part B<br />
What is the differential equation satisfied by the current after time ?<br />
Part B.1<br />
Kirchhoff's loop law<br />
Part not displayed<br />
Express in terms of , , and .<br />
ANSWER:<br />
= Answer not displayed<br />
Part C<br />
What is the expression for obtained by solving the differential equation that satisfies after ?<br />
Part C.1<br />
Hint C.2<br />
Separation of variables<br />
Integrating<br />
Part not displayed<br />
Hint not displayed<br />
Express your answer in terms of the initial current , as well as , , and .<br />
ANSWER: = Answer not displayed<br />
Part D<br />
What is the time constant<br />
of this circuit?<br />
Hint D.1<br />
Hint D.2<br />
Definition of time constant<br />
The time constant for this circuit<br />
Hint not displayed<br />
Hint not displayed<br />
Express your answer in terms of and ?<br />
ANSWER: = Answer not displayed<br />
Growth of Current in an L-R Circuit<br />
http://session.masteringphysics.com/myct<br />
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