NIU ELE 100 Exam 2

How much current flows in a circuit with a 18-volt battery and six 1 ohm resistors (bulbs) in series?

3 A Solution: 1Ω + 1Ω + 1Ω + 1Ω + 1Ω + 1Ω = 6Ω 18V / 6Ω = 3A

If 5 V and 16 V power supplies are connected in series-opposing, what is the total voltage?

11V Solution: 16V - 5V = 11V

If the first resistor R1 in the circuit shown below opens up, what will the total current be? I2 = R2 = 128 mA I1 = R1 = 42 mA IT -> Vs

128mA Solution: R2 = 128mA

Voltage sources cannot be added in series if they equal values and same polarities.

False

For the circuit shown here, which statement is true? R5 = 6 Ω - parallel R4 = 4 Ω - series R3 = 10 Ω - parallel to R5 and R4 R2 = 30 Ω - series R1 = 15 Ω - series VT = 100 V

none of the choices listed here

In a parallel circuit as shown below, if one of the bulb burns out what happens to the rest of the bulbs in the circuit?

will continue to glow

What is the main current flowing in the circuit shown below? 7.5 Ω - series 2 Ω - series 3 Ω - series 5 Ω - parallel to 2 Ω and 3 Ω 15 V

1.5 A Solution: 2Ω + 3Ω = 5Ω 5Ω / 2 = 2.5Ω 2.5Ω + 7.5Ω = 10Ω 15V / 10Ω = 1.5A

What is the total current in the circuit shown here? I2 = 128 mA I1 = 42 mA IT -> Vs

170mA Solution: 128mA + 42mA = 170mA

What value of resistor would produce a current of 3 A in a circuit when a 12 V battery is connected?

4 Ω Solution: R = V / I 12V / 3A = 4Ω

What is the voltage drop across each resistor in the circuit shown here? 1Ω 2Ω 3Ω 12V

4V, 6V, 2V Solution: 3Ω + 2Ω + 1Ω = 6Ω 12V / 6Ω = 2A 2Ω * 2A = 4V 3Ω * 2A = 6V 1Ω * 2A = 2V

What is the current flowing in a 20Ω resistor, when the voltage E=120Volts?

6 Amps Solution: I = V / R 120V / 20Ω = 6A

If you have two 3000 ohm resistors in series, what is the total resistance?

6 kΩ Solution: 3 kΩ + 3 kΩ = 6 kΩ

What is the total current flowing in the circuit shown here? 1 Ω - parellel 1 Ω - parellel 2 Ω - series 20 V

8 Amps Solution: 1Ω / 2 = 0.5Ω 2Ω + 0.5Ω = 2.5Ω 20V / 2.5Ω = 8A

What is the total equivalent resistance for the circuit shown here? R4 = 50 Ω - parallel R3 = 50 Ω - parallel R2 = 15 Ω - series R1 = 10Ω - parallel to R3 and R2 RT ->

8 Ω Solution: 50Ω / 2 = 25Ω 25Ω + 15Ω = 40Ω 40Ω * 10Ω = 400Ω 40Ω + 10Ω = 50Ω 400Ω / 50Ω = 8Ω

If R1 is disconnected (or removed) from the circuit shown below, what would be the total resistance? R3 = 900 Ω - parallel R2 = 100 Ω - parallel R1 = 10 Ω - series

90 Ω Solution: 900Ω * 100Ω = 90,000Ω 900Ω + 100Ω = 1,000Ω 90,000Ω / 1000Ω = 90Ω

If R2 is disconnected (or removed) from the circuit shown below, what would be the total resistance? R3 = 900 Ω - parallel R2 = 100 Ω - parallel R1 = 10 Ω - series

910 Ω Solution: 900Ω + 10Ω = 910Ω

If R2 is disconnected from the circuit shown below, what would be the total resistance? R3 = 900 Ω - parallel R2 = 100 Ω - parallel R1 = 10 Ω - series

910 Ω Solution: 900Ω + 10Ω = 910Ω

If the resistance in a circuit decreases while the voltage stays the same, what happens to the current?

Current increases

What are the readings on the ammeters (these are instruments to measure the current) A1 and A4 in the circuit shown below if A2 = A3 = 2 Ampere? A1 -> A4 A2 X A3 X

A1 = 4 Amperes & A4 = 4 Amperes

In a series connected circuit with 100 Christmas bulbs, if one bulb burns out what happens to the remaining bulbs?

All bulbs turn off

The first goal(s) to accomplish in analyzing a complex series-parallel circuit is to:

Determine the total resistance and the main current first.

If the voltage in an electrical circuit containing a lightbulb is increased, what happens to the brightness of the bulb?

Increases

How will an open resistor affect a series circuit?

No current will flow in the circuit.

Given a series circuit containing resistors of different values, which statement is not true?

The voltage drop across each resistor is the same.

What makes a circuit a parallel circuit?

There is MORE than one path for the current to flow.

How do you find the total resistance in a parallel circuit?

Total resistance RT is the reciprocal of the sum of the reciprocal of all the individual resistances. 1/RT = 1/R1 + 1/R2 + 1/R3 +.......

The voltage across any branch of a parallel circuit is_____________.

is the same as the other parallel elements

An ammeter is always connected in ______________ with the other components in an electrical circuit.

series

Which law is described by the following equation: V or E = I x R?

Ohm's Law

What is the total resistance in the circuit shown below? R2 = 10 Ω - parallel R1 = 10 Ω - parallel R3 = 5 Ω - series V1 = 20 V

10 Ω Solution: 10Ω / 2 = 5Ω 5Ω + 5Ω = 10Ω

In the circuit shown above, apply Kirchoff's Current Law (KCL), and determine I2. I1 = 7 A ^ I3 = 4 A ^ I2 = ->

3 A

How much current flows in a circuit with a 1.5-volt battery and three 1 ohm resistances (bulbs) in series?

0.5 A Solution: 1Ω + 1Ω + 1Ω = 3Ω 1.5V / 3Ω = 0.5A

What is the total current flowing in the circuit shown below? 6 Ω - series10 Ω - series 6 Ω - parallel to 6 Ω and 10 Ω 3 Ω - series 2 Ω - series 5 Ω - parallel to 3 Ω and 2 Ω 15 V

0.96 Amps Solution: 6Ω / 2 = 3Ω 10Ω + 3Ω = 13Ω 2Ω + 3Ω = 5Ω 5Ω / 2 = 2.5Ω 13 + 2.5Ω = 15.5Ω 15V / 15.5Ω = 0.96A

What are the values of the currents I1 and I2 in the circuit shown below? R4 = 25 Ω - parallel R3 = 5 Ω - series R2 = 10 Ω - parallel to R4 and R3 R1 = 2.5 Ω - series 24 V

1.8 Amps and 0.6 Amps Solution: 25Ω + 5Ω = 30Ω 1 / 30Ω + 1 / 10Ω = 0.033Ω + 0.1Ω = 0.133Ω 1 / 0.133Ω = 8Ω 8Ω + 2.5Ω = 10.5Ω 24V / 10.5Ω = 2.29A I1 = (25Ω + 5Ω) = 30Ω 30Ω / (30Ω + 10Ω) = 30Ω / 40Ω = 0.75Ω 0.75Ω * 2.29A = 1.8A I2 = 10Ω / (30Ω + 10Ω) = 10Ω / 40Ω = 0.25Ω 0.25Ω + 2.29A = 0.6A

What are the values of the currents I1 and I2 in the circuit shown below? R4 = 25 Ω - parallel - I2 R3 = 5 Ω - series R2 = 10 Ω - parallel to R4 and R3 - I1 R1 = 2.5 Ω - series - I TOT 24 V

1.8 Amps and 0.6 Amps Solution: 25Ω + 5Ω = 30Ω 1 / 30Ω + 1 / 10Ω = 0.033Ω + 0.1Ω = 0.133Ω 1 / 0.133Ω = 8Ω 8Ω + 2.5Ω = 10.5Ω 24V / 10.5Ω = 2.29A I1 = (25Ω + 5Ω) = 30Ω 30Ω / (30Ω + 10Ω) = 30Ω / 40Ω = 0.75Ω 0.75Ω * 2.29A = 1.8A I2 = 10Ω / (30Ω + 10Ω) = 10Ω / 40Ω = 0.25Ω 0.25Ω + 2.29A = 0.6A

A circuit has three 30 Ω resistors connected in parallel. What is the total equivalent resistance of the circuit?

10 Ω Solution: 1 / 30Ω + 1 / 30Ω + 1 / 30Ω = 0.033Ω + 0.033Ω + 0.033Ω = 0.099Ω 1 / 0.099Ω = 10Ω

What is the total resistance in the circuit shown here? 7.5 Ω - series 2 Ω - series 3 Ω - series 5 Ω - parallel to 2 Ω and 3 Ω 15 V

10 Ω Solution: 2Ω + 3Ω = 5Ω 5Ω / 2 = 2.5Ω 2.5Ω + 7.5Ω = 10Ω

What is the total resistance between the terminals A &B in the circuit shown here? R3 = 900 Ω - parallel R2 = 100 Ω - parallel R1 = 10 Ω - series

100 Ω Solution: 900Ω * 100Ω = 90,000Ω 900Ω + 100Ω = 1,000Ω 90,000Ω / 1,000Ω = 90Ω 90Ω + 10Ω = 100Ω

What is the total equivalent resistance for the circuit shown here? 6 Ω - series 10 Ω - series 6 Ω - parallel to 6 Ω and 10 Ω 3 Ω - series 2 Ω - series 5 Ω - parallel to 3 Ω and 2 Ω 15 V

15.5 Ω Solution: 6Ω / 2 = 3Ω 10Ω + 3Ω = 13Ω 2Ω + 3Ω = 5Ω 5Ω / 2 = 2.5Ω 13Ω + 2.5Ω = 15.5Ω

What is the voltage drop across the resistor R1 ( 2Ω) in the circuit shown here? 1 Ω - parellel 1 Ω - parellel 2 Ω - series 20 V

16 V Solution: 1Ω / 2 = 0.5Ω 0.5Ω + 2Ω = 2.5Ω 20V / 2.5Ω = 8A 2Ω * 8A = 16V

Determine the amount of power absorbed in a circuit if a 6V battery is used and a 3A of current is flowing in the circuit?

18 Watts Solution: P = V * I 6V * 3A = 18W

What is the current flowing through each of the two 10 Ω resistors in the circuit shown below? R2 = 10 Ω - parallel R1 = 10 Ω - parallel R3 = 5 Ω - series V1 = 20 V

1A, 1A Solution: 10Ω / 2 = 5 Ω 5Ω + 5Ω = 10Ω 20V / 10Ω = 2A 2A / 2 = 1A

What is the main current flowing in the circuit shown below? R2 = 10 Ω - parallel R1 = 10 Ω - parallel R3 = 5 Ω - series V1 = 20 V

2 A Solution: 10Ω / 2 = 5Ω 5Ω + 5Ω = 10Ω 20V / 10Ω = 2A

What is the current flowing in the circuit shown here? 1Ω 2Ω 3Ω 12V

2 A Solution: 3Ω + 2Ω + 1Ω = 6Ω 12V / 6Ω = 2A

If a battery produced 12.6 Volts and what would be the current flow be for a 6 Ohm resistor?

2.1 A Solution: I = V / R 12.6V / 6Ω = 2.1A

Current through a 100 Ω resistor that is to be used in a circuit is 0.15 A. What is the power being absorbed by the resistor?

2.25 Watts P = I^2 * R 0.15^2 A * 100Ω = 0.0225A * 100Ω = 2.25W

What is the total equivalent resistance for the circuit shown here? 1 Ω - parellel 1 Ω - parellel 2 Ω - series 20 V

2.5 Ω Solution: 1 / 2 = 0.5Ω 2Ω + 0.5Ω = 2.5Ω

A circuit has a current of 2.15 A flowing through it. How many milli amps (mA) does that equal?

2150 mA