Quiz 10

Question 1

In a parallel circuit, the ? in the circuit is equal to the sum of the branch currents.

a. power
b. source voltage
c. total current flow
d. total resistance

Answer 1

c. total current flow

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 115

Question 2

Parallel circuits are circuits that have ? .

a. more than one path for current to flow
b. more than one voltage source
c. only direct current (DC) flow
d. one voltage source

Answer 2

a. more than one path for current to flow

Question 3

In the circuit, the R2 resistor branch will allow greater current flow than the R1 resistor branch.

R₁ = 6 Ω
R₂ = 8 Ω

True or False?

Answer 3

False

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

In a parallel circuit, a decrease in resistance means an increase in current flow.

Question 4

The formula for finding total current in a parallel circuit when branch currents are known is Iₜ = Iᵣ₁ + Iᵣ₂ + Iᵣ₃ + Iᵣ₄ + ….Iₙ.

True or False?

Answer 4

True

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 5

Adding more resistive branches to a parallel circuit will increase total circuit resistance and decrease the total circuit current.

True or False?

Answer 5

False

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 117

Question 6

Which equation should be used to find the total current of a parallel circuit when the source voltage and total resistance are known?

a. Iₜ = Eₜ × Rₜ
b. Iₜ = Eₜ / Rₜ
c. Iₜ = Eₜ² / Pₜ
d. Iₜ = Rₜ / Eₜ

Answer 6

b. Iₜ = Eₜ / Rₜ

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 117

Question 7

A parallel circuit is also a ? .

a. circuit where the current is equal in all branches
b. circuit where the total circuit resistance is equal to the total circuit current
c. current divider circuit
d. single source circuit

Answer 7

c. current divider circuit

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 8

In a parallel circuit, the amount of current flow through each branch is inversely proportional to the resistance value.

True or False?

Answer 8

True

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 117

Question 9

If three equal-rated batteries were connected in parallel to a load, each battery would provide one-third of the total current to the load.

True or False?

Answer 9

True

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 124

Question 10

The current flow through the switch and fuse in this circuit is ? .

Eₜ = 12 V
R₁ = 6 Ω
R₂ = 4 Ω

a. 4 A
b. 5 A
c. 6 A
d. 10 A

Answer 10

b. 5 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pgs. 116-117

2 Resistors :

1 / Rₜ = 1 / R₁ + 1 / R₂

Rₜ = R₁ × R₂ / R₁ + R₂

3 Resistors

1 / Rₜ = 1 / R₁ + 1 / R₂ + 1 / R₃

Rₜ = R₁ × R₂ × R₃ / R₁R₂ + R₁R₃ + R₂R₃

Question 11

This three branch parallel circuit has a total current flow of ? .

Eₜ = 24 V
R₁ = 90 Ω
R₂ = 90 Ω
R₃ = 90 Ω

a. 3 A
b. 6 A
c. 8 A
d. 10 A

Answer 11

c. 8 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pgs. 116-117

Question 12

In a parallel circuit, the ? across each branch of the circuit must be equal.

a. current
b. resistance
c. voltage
d. wattage

Answer 12

c. voltage

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 115

Question 13

The battery bank in this circuit supplies a total current of ? to the three branch load.

Eˢ¹ = 24 V
Eˢ² = 24 V
R₁ = 180 Ω
R₂ = 180 Ω
R₃ = 180 Ω

a. 4 A
b. 6 A
c. 8 A
d. 12 A

Answer 13

a. 4 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pgs. 116-117

Question 14

The current flow through each of these equally sized lamps is ? .

Eˢ¹ = 18 V
Eˢ² = 18 V
R₁ = 240 Ω
R₂ = 240 Ω
R₃ = 240 Ω
R₄ = 240 Ω

a. 0.5 A
b. 0.75 A
c. 1.25 A
d. 1.5 A

Answer 14

b. 0.75 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 15

This circuit has a current flow of ? through the switch and fuse.

Eˢ¹ = 30 V
R₁ = 90 Ω
R₂ = 45 Ω
R₃ = 60 Ω

a. 0.5 A
b. 1 A
c. 1.25 A
d. 2 A

Answer 15

c. 1.25 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 16

In the circuit, the current through the R1 resistor branch is ? and the current through the R2 branch is ? .

a. 0.5 A / 0.25 A
b. 0.75 A / 0.5 A
c. 1 A / 0.75 A
d. 1.25 A / 1 A

Answer 16

b. 0.75 A / 0.5 A

Question 17

This two branch circuit has a 20-ohm resistor, R1, and a resistor of unknown value, R2. With the given values, find the current flow through the R2 resistor. Then, using Ohm’s Law and the found IR2 value, find the resistance of R2.

Eˢ¹ = 12 V
R₁ = 20 Ω
R₂ = ? Ω
Iₜ = x A

a. 12 Ω
b. 18 Ω
c. 24 Ω
d. 30 Ω

Answer 17

c. 24 Ω

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 18

Use the reciprocal method to find the equivalent resistance of the five branches in this circuit. With the given voltage and total resistance, use Ohm’s Law to find the total current flow.

Eₜ = 36 V
R₁ = x Ω
R₂ = x Ω
R₃ = x Ω
R₄ = x Ω
R₅ = x Ω

a. 3.5 A
b. 5 A
c. 7.5 A
d. 9 A

Answer 18

d. 9 A

Question 19

This circuit has a 36-volt supply and six identical resistors in parallel. The total equivalent resistance is four ohms. Find the total circuit current to solve for the current through each lamp. Each lamp has a current flow of ? .

Eₜ = 36 V
R₁ = x Ω
R₂ = x Ω
R₃ = x Ω
R₄ = x Ω
R₅ = x Ω

a. 0.75 A
b. 1 A
c. 1.25 A
d. 1.5 A

Answer 19

d. 1.5 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 20

The current flow through the switch and fuse in this circuit is ? .

Eₜ = 54 V
R₁ = 120 Ω
R₂ = 60 Ω
R₃ = 24 Ω

a. 2.8 A
b. 3.6 A
c. 4.2 A
d. 4.8 A

Answer 20

b. 3.6 A

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116

Question 21

Use the law of proportionality to find the current flow through the R2 resistor. The R2 branch current is ? .

Iₜ = A
R₁ = 20 Ω
R₂ = 10 Ω

a. 3 A
b. 6 A
c. 9 A
d. 12 A

Answer 21

d. 12 A

DC Theory 3rd Ed. Textbook, Chap. 7, Pg. 161

Question 22

This circuit is provided with overcurrent protection by a six-ampere cartridge fuse. Each lamp has a resistance of 12 ohms. How many of the branch switches can be closed before the fuse melts?

Eₜ = 18 V
Iᶠ¹ = 6 A
R₁ = 120 Ω
R₂ = 120 Ω
R₃ = 120 Ω
R₄ = 120 Ω
R₅ = 120 Ω

a. 2
b. 3
c. 4
d. 5

Answer 22

c. 4

DC Theory 3rd Ed. Textbook, Chap. 5, Pg. 116