In lab, you come across an old resistor and inductor that are not labeled. (It i

Question

In lab, you come across an old resistor and inductor that are not labeled. (It is a real inductor, made from a long coiled wire, so it has some resistance.) You connect them in a series circuit as shown below, along with a battery (epsilon = 3.0 V) and a switch. You hook up an ammeter to measure the current in the circuit, and make a graph as you close and then open the switch. The graph below begins at the moment you open the switch after it has been closed for a while. Use the graph to find the total resistance in the circuit (from the resistor and inductor combined). Show your work and explain your reasoning. Use the graph to find the inductance of the inductor. Show your work and explain your reasoning.

Explanation / Answer

a)

From Graph Maximum Current is

Imax =0.3 A

Since Imax=E/R

=>R=E/Imax =3/0.3

R=10 ohms

b)

From graph at t=0.5 s=>I=0.12 A

For a RL circuit ,Discharging current equation is given by

I=Imaxe-t/T

0.12=0.3e-0.5/T

-0.5/T =Ln(0.4)

T=0.5456 s

since T=L/R

=>L=TR=0.5456*10

L=5.46 H

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.