1. Two resistors, one 130-ohm and the other 210-ohm, are connected in parallel. The resistors are then connected to a battery. If the current through the entire circuit is 0.31 A, what is the voltage of the battery?
2. Resistors R1, R2, and R3 are connected in parallel. R1 is 68 ohm and R2 is 93 ohm. The equivalent resistance of the parallel combination is 26-ohm. What is the resistance of R3?
3. Four identical resistors are connected in parallel. The equivalent resistance of the parallel combination is 4.5-ohms. What is the resistance of each resistor?
4. A 25-ohm resistor, a 55-ohm resistor, and a 75-ohm resistor are connected in parallel and placed across a 9.0-V battery. (a.) What is the equivalent resistance of the parallel circuit? (b.) What is the current through the entire circuit? (c.) What is the current through each branch of the circuit?
5. A 120-V household circuit that contains a 320-W television, a 1.0 x102-W lamp, and a 1350-W heater is connected to a 20.0-A fuse. Will the fuse melt if all three devices are operating simultaneously? Explain.
6. Before going to work each morning, Gene runs his 18 ohm toaster, 11-ohm electric frying pan, and 14-ohm electric coffee maker, all at the same time. The three are connected in parallel across a 120-V line. (a) What is the current through each appliance? (b) If a household circuit could carry a maximum current of 15-A, would Gene be able to run all of these appliances at the same time?
2. Resistors R1, R2, and R3 are connected in parallel. R1 is 68 ohm and R2 is 93 ohm. The equivalent resistance of the parallel combination is 26-ohm. What is the resistance of R3?
3. Four identical resistors are connected in parallel. The equivalent resistance of the parallel combination is 4.5-ohms. What is the resistance of each resistor?
4. A 25-ohm resistor, a 55-ohm resistor, and a 75-ohm resistor are connected in parallel and placed across a 9.0-V battery. (a.) What is the equivalent resistance of the parallel circuit? (b.) What is the current through the entire circuit? (c.) What is the current through each branch of the circuit?
5. A 120-V household circuit that contains a 320-W television, a 1.0 x102-W lamp, and a 1350-W heater is connected to a 20.0-A fuse. Will the fuse melt if all three devices are operating simultaneously? Explain.
6. Before going to work each morning, Gene runs his 18 ohm toaster, 11-ohm electric frying pan, and 14-ohm electric coffee maker, all at the same time. The three are connected in parallel across a 120-V line. (a) What is the current through each appliance? (b) If a household circuit could carry a maximum current of 15-A, would Gene be able to run all of these appliances at the same time?
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1) (130 x 210)/(130 + 210) = 80.294 ohms.
Voltage E = (IR) = 0.31 x 80.294, = 24.89V.
2) 1/ ((1/26) - (1/68) + (1/93)) = 76.9 ohms.
3) 18 ohms.
4) (a) 1/ (1/25) + (1/55) + (1/75) = 13.983 ohms.
(b) Current I = (E/R) = 9/13.983, = 0.644A.
(c) Through 25R = (E/R) = 9/25 = 0.36A.
Through 55R = 0.164A.
Through 75R = 0.12A. Note how all 3 added equals circuit current (b).
5) (320 + 100 + 1350) = 1,770W.
(1,770/120) = current of 14.75A.
No, current is just within fuse capability.
6) (a) Toaster current I = (E/R) = 120/18, = 6.67A.
Frying pan I = (120/11) = 10.91A.
Coffee maker I = (120/14) = 8.57A.
(b) (6.67 + 10.91 + 8.57) = 26.15A.
NO.
Voltage E = (IR) = 0.31 x 80.294, = 24.89V.
2) 1/ ((1/26) - (1/68) + (1/93)) = 76.9 ohms.
3) 18 ohms.
4) (a) 1/ (1/25) + (1/55) + (1/75) = 13.983 ohms.
(b) Current I = (E/R) = 9/13.983, = 0.644A.
(c) Through 25R = (E/R) = 9/25 = 0.36A.
Through 55R = 0.164A.
Through 75R = 0.12A. Note how all 3 added equals circuit current (b).
5) (320 + 100 + 1350) = 1,770W.
(1,770/120) = current of 14.75A.
No, current is just within fuse capability.
6) (a) Toaster current I = (E/R) = 120/18, = 6.67A.
Frying pan I = (120/11) = 10.91A.
Coffee maker I = (120/14) = 8.57A.
(b) (6.67 + 10.91 + 8.57) = 26.15A.
NO.
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Adding resistances.
In series. Rt = R1 + R2 + R3
In parallel. 1/Rt = 1/R1 + 1/R2 + 1/R3.
Voltage in a circuit. E in volts, I in amps. R in ohms. P in Watts.
E = I x R. I = E/R. R = E/I. P = E x I. P = I x I x R. P = E x E/R.
Do your own maths.
In series. Rt = R1 + R2 + R3
In parallel. 1/Rt = 1/R1 + 1/R2 + 1/R3.
Voltage in a circuit. E in volts, I in amps. R in ohms. P in Watts.
E = I x R. I = E/R. R = E/I. P = E x I. P = I x I x R. P = E x E/R.
Do your own maths.