Part N: Short Answer (16 pts) Instructions: You MUST answer question number one.
ID: 2304931 • Letter: P
Question
Part N: Short Answer (16 pts) Instructions: You MUST answer question number one. In addition select either two OR three (both are not Extro credit Complete both questions 2 AND 3 1. (10 pts) Use the circuit diagram to answer the questions below R1 50 0 R2 70? a) (2 pts) What is the total resistance of the circuit? b) (1 pt) What is the current through the battery? c) (3 pts) What is the current through each resistor? d) (3 pts) What is the potential difference (voltage across each resistor? (1 pt) Which resistor has the greatest electric power? e) R3 100 12 VExplanation / Answer
a]
R1 and R2 are in series and their sum is:
R = 50 + 70 = 120 ohms
this is parallel to R3. Therefore, the total resistance of the circuit will be:
Req = [(1/120) + (1/100)]-1 = 54.545 ohms
b] The current through the battery will be:
I = V/Req = 12/54.545 = 0.22 A.
c] Voltage across R3 is 12 volts and so current through it is:
iR3 = 12/100 = 0.12 A.
therefore, current in R1 and R2 will be: I = 0.22 - 0.12 = 0.10 A
the current in R1 and R2 will be the same since they are connected in series.
d] Potential difference across R3 = potential difference across the battery = 12 volts
Potential difference across R1 is:
V = 0.1(50) = 5 volts
and across R2 is: V' = 0.1(70) = 7 volts.
e] Electrical power is given by:
P = VI
so, the greatest electrical power will be for the resistor for which the potential difference across it and the current passing through it is maximum. This is true for R3 in this circuit and so R3 has greatest electrical power.