Consider the network of four resistors shown in the diagram, where R 1 = 2.00 ?
ID: 1424819 • Letter: C
Question
Consider the network of four resistors shown in the diagram, where R1 = 2.00 ? , R2 = 5.00 ? , R3 = 1.00 ? , and R4 = 7.00 ? . The resistors are connected to a constant voltage of magnitude V. (Figure 1)
Find the equivalent resistance RA of the resistor network.
Express your answer in ohms.
B.
Two resistors of resistance R5 = 3.00 ? and R6 = 3.00 ? are added to the network, and an additional resistor of resistance R7 = 3.00 ? is connected by a switch, as shown in the diagram..(Figure 2) Find the equivalent resistance RB of the new resistor network when the switch is open.
Express your answer in ohms.
C.
Find the equivalent resistance RC of the resistor network described in Part B when the switch is closed.
Express your answer in ohms.
Explanation / Answer
A) For the first figure
R3 and R4 are series then R34 = 1+7 = 8
then R12 = (2*5)/(2+5) = 1.42 ohm and R34 are in series
then RA = 1.42+8 = 9.42 ohm
B) when switch is open
no effect of the inclusion of R7
then R345 = 1+7+3 = 11 ohm
R16 = 2+3 = 5 ohm
R162= 5*5/(5+5) = 2.5 ohm
RB = 2.5+11 = 13.5 ohm
C) when the switch is closed,then
R47 = (7*3)/(7+3) = 2.1 ohm
R3,R47 and R5 are in series then
R3475 = 1+2.1+3 = 6.1 ohm
R162 = 2.5 ohm
RC = 6.1+2.5= 8.6 ohm