The switch in the circuit shown below is a two-way switch; to prevent sparking,
ID: 2216478 • Letter: T
Question
The switch in the circuit shown below is a two-way switch; to prevent sparking, the switch is also a "make-before-break" switch, meaning that, in moving fromatob, the switch makes contact atban instant before losing contact ata. When the switch is in positiona, the inductorLis in series with the battery and resistorRa. When the switch is inpositionb,the inductorLis in series with resistorRb.
Assume that Ra= 8.0?, L= 6.0H,Rb= 20.0?, and VB= 100V,and also assume that the switch is first moved to positiona. After a long time, the switch is then moved to positionb. Immediately after moving the switch to positionb, what will be the absolute value of the induced EMF in the inductorL?
Explanation / Answer
when switch is in long connection with (a)
Ra = 8 , V = 100 V , L = 6 H
Current in the circuit = V/Ra = 12.5 A
when moved to position (b)
Potential drop across resistor Rb = IR = 20 * 12.5 = 250 V
This is the potential across inductor.
V = 250 Volts