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(c31p54) In the diagram is shown an RL circuit with a switch. = 100.0 V , R 1 =

ID: 1453693 • Letter: #

Question

(c31p54) In the diagram is shown an RL circuit with a switch. = 100.0 V, R1 = 70.0 , R2 = 140.0 and L = 45.0 H. Find the values of i1, the current through resistor R1 and i2, the current through resistor R2, the current through the switch, the potential difference across R2, the potential difference across L and the rate of change of the current di2/dt in the time just after the closing of the switch.


What is i1 just after the switch is closed?

What is i2 just after the switch is closed?

What is the value of the current in the switch just after the switch is closed?

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

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

What is the rate of change of the current di2/dt in the time just after the closing of the switch?


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

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

What is the value of the current in the switch a long time after the switch is closed?

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

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

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

Explanation / Answer

i1 just after the switch is closed = 100/70 = 1.428 A

i2 just after the switch is closed = 0 A

the potential difference across L just after the switch is closed = 100 V

rate of change of the current di2/dt in the time just after the closing   = 100/45 = 2.22 A/sec

i1 a long time after the switch is closed   =   100/70 = 1.428 A

i2 a long time after the switch is closed    =   100/140 =   0.714 A

value of the current in the switch a long time after = (1.428 + 0.714) = 2.142 A

the potential difference across R2 a long time after   = 100 V

potential difference across L a long time after = 0 V

rate of change of the current di2/dt a long time after   =   0 A/sec