53. ssm The drawing shows a circuit that contains a battery, two resistors, and a switch. What is the equivalent resistance of the circuit when the switch is (a) open and (b) closed? What is the total power delivered to the resistors when the switch is (c) open and (d) closed?

 

w1021

 

When switch is open only 65.0 Ω is part of the circuit, so

 

 

When the switch is closed then the 65.0 Ω is in parallel with the 96.0 Ω resistor and we find the combined or total resistance as

 

 

or

 

To find the power use the expression

 

So when the switch is open

 

 

When switch is closed we can find power two ways, first use the total resistance

 

 

Or we can find power in each resistor and add them

 

 

Again a bit of rounding error.

 

 

 

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This page last updated on June 17, 2018