Suppose you had a circuit with three resistors in series and you measured I=7.0 milliamps; V = 14.7 volts; V1= 3.5 volts and V2 = 1.4 volts. What would be the voltage across the third resistor? What would its resistance be?
V =V1+v2+v3
14.7 =3.5+1.4+v3
v3 =9.8 ans
v3 =IR3
9.8/7*10^-3 =R3 =1400 ohm
To find the voltage across the third resistor, you can use the formula:
V = V1 + V2 + V3
In this case, you know that V = 14.7 volts, V1 = 3.5 volts, and V2 = 1.4 volts. Let's substitute these values into the formula:
14.7 volts = 3.5 volts + 1.4 volts + V3
Now, let's solve for V3:
V3 = 14.7 volts - (3.5 volts + 1.4 volts)
V3 = 14.7 volts - 4.9 volts
V3 = 9.8 volts
Therefore, the voltage across the third resistor would be 9.8 volts.
To find the resistance of the third resistor, you can use Ohm's Law:
V = I * R
In this case, you know that V3 = 9.8 volts and I = 7.0 milliamps (which is equivalent to 0.007 amps). Let's substitute these values into the formula:
9.8 volts = 0.007 amps * R
Now, let's solve for R:
R = 9.8 volts / 0.007 amps
R ≈ 1400 ohms
Therefore, the resistance of the third resistor would be approximately 1400 ohms.