In the diagram is shown an RL circuit with a switch. ? = 105.0 V , R 1 = 60.0 ?
ID: 1375458 • Letter: I
Question
In the diagram is shown an RL circuit with a switch. ? = 105.0 V, R1 = 60.0 ?, R2 = 120.0 ? and L = 60.0 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 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?
In the diagram is shown an RL circuit with a switch. ? = 105.0 V, R1 = 60.0 ?, R2 = 120.0 ? and L = 60.0 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 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?Explanation / Answer
1)
Just after closing the switch, the inductor will be open circuited.
And thus the voltage across inductor = emf of battery = 105 V
Butm voltage across inductor = L*dI2/dt = 105
So, dI2/dt = 105/L = 105/60 = 1.75 A/s <-------answer
2)
After a long time inductor will short out and thus R1 and R2 seem to be in parallel connection
So, Rnet = R1*R2/(R1+R2) = 40 ohm
So, I1 = E/R1 = 105/60 = 1.75 A <------answer
3)
So, I2 = E/R2 = 105/120 = 0.875 A <-------answer
4)
Current in the switch = I1 + I2 = 2.63 A <------answer
5)
Potential across R2 = E = 105 V <--------- as L gets shorted
6)
Potential across L = 0 V <----- as it gets shorted