Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

The diagram shows an RL circuit with a switch. ? = 120.0 V, R1 = 25.0 ?, R2 = 50

ID: 2235741 • Letter: T

Question

The diagram shows an RL circuit with a switch. ? = 120.0 V, R1 = 25.0 ?, R2 = 50.0 ?, and L = 50.0 H.

a. What is i1 just after the switch is closed?

b. What is i2 just after the switch is closed?

c. What is the magnitude of the current in the switch just after it is closed?

d. What is the potential difference across R2 just after the switch is closed?

e. What is the potential difference across L just after the switch is closed?

f. What is the rate of change di2/dt of the current just after the switch is closed?

g. What is i1 a long time after the switch is closed?

h. What is i2 a long time after the switch is closed?

i. What is the magnitude of the current in the switch a long time after it is closed?

j. What is the potential difference across R2 a long time after the switch is closed?

k. What is the potential difference across L a long time after the switch is closed?

l. What is the rate of change di2/dt of the current a long time after the switch is closed?


Explanation / Answer

a) i1 just after the switch is closed=e/r1=120/25=4.8 A

b) i2 just after the switch is closed = 0 (inductor acts as open circuit)

c) current through the switch (i)= i1+i2=4.8 A

d) potential difference across R2 = 0 (since i2=0)

e) potential difference across L = 120V (since inductor acts as open circuit)

f)the rateof change of i2 just after switch is closed

using Ldi2/dt= v

=> di2/dt=120/50=2.4 A/s

g)i1 long after the switch is closed=e/r1=4.8 A

h) i2 long after the switch is closed=e/r2 =120/50=2.4 A (long after switch is closed inductor acts as short circuit)

i) current through the switch after the switch is closed(i)= i1+i2=4.8 +2.4 = 7.2 A

j) potential across R2 long after the switch is closed =120 V (long after switch is closed inductor acts as short circuit)

k) potential across L long after the switch is closed =0 V (long after switch is closed inductor acts as short circuit)

l) change in i2 = di2/dt = 0 A/s