Deck 9: Branch, Loop, and Node Analyses

Question 1

The loop current is not necessarily the actual current in a branch.

Answer 1

True

Question 2

A loop is a closed current path in a circuit.

Answer 2

True

Question 3

A node is a junction of two or more current paths.

Answer 3

False

Question 4

What circuit law is used in the mesh current method?

A) Kirchhoff's current law
B) Kirchhoff's voltage law
C) the power law
D) Ohm's law

Question 5

To convert from a wye to an equivalent delta, superimpose the two and take the sum of the products of the wye, then divide by the opposite wye resistor from the delta resistor you are trying to find.

Question 6

An advantage of mesh currents over branch currents is:

A) The mesh current method can be applied to circuits with any number of loops.
B) The mesh current method requires fewer equations than the branch method.
C) There are no negative answers for current.
D) There are no advantages.

Question 7

A node is where the voltage is connected to the circuit.

Question 8

Mesh currents flow in a counter-clockwise direction through each loop.

Question 9

The branch method is based on loop currents.

Question 10

Loop/Mesh analysis uses simultaneous equations to calculate the current through each component.

Question 11

The branch current method involves using:

A) loops and nodes
B) voltages and nodes
C) junctions and nodes
D) loops and junctions

Question 12

Which of the following are useful for analyzing circuits with two or more voltage or current sources?

A) mesh current method
B) node-voltage method
C) branch current method
D) all of the above

Question 13

The rule, when solving for several unknown quantities is:

A) You must have the same number of equations as there are unknown values.
B) You must use substitution.
C) You must use determinants.
D) Use Ohm's law.

Question 14

In the equation; 5I1 - 8I2 = 10, which is the coefficient for I1?

A) 10
B) -8
C) 5
D) 8

Question 15

The loop current direction must be drawn:

A) counter-clockwise
B) clockwise
C) It doesn't matter, as long as you are consistent.

Question 16

Delta to wye configurations are used in bridge circuits.

Question 17

What is a loop current?

A) Loop currents are assigned currents
B) Loop currents are actual currents.

Question 18

Simultaneous equations can be solved by substitution or by using determinants.

Question 19

What is the significance of a negative sign in the answer for current, when solving network problems?

A) It means you must chose the correct direction for the actual, net, current flow.
B) It means that the negative current flows in the opposite direction from the assigned current.
C) It means you must subtract the negative value from the other value.
D) It means there is a negative current flow.

Question 20

What circuit law is used in the node voltage method?

A) Kirchhoff's current law
B) Kirchhoff's voltage law
C) Ohm's law
D) the power law

Question 21

Give the two equations, 2I₁ = 8 - 5I₂ and 0 = 4I₂ - 5I₁ + 6, in standard form.

A) 2I₁ + 3I₂ = 6
4I₁ - 2I₂ = 8
B) 2I₁ + 5I₂ = 8
5I₁ - 4I₂ = 6
C) 3I₁ + 5I₂ = 6
2I₁ + 4I₂ = 8

Question 22

See Figure 9-3. Using R = 100 Ω, compute the current through the 50 Ω resistor.

A) 2.14 mA
B) 21.47 µA
C) 21.47 A
D) 21.47 mA

Question 23

See Figure 9-3. If R = 100 Ω, compute the current through the 50 Ω resistor. Use the delta-wye conversion method.

A) 21.5 mA, Left to Right
B) 31.8 mA, Right to Left
C) 21.5 mA, Right to Left
D) 31.8 mA, Left to Right

Question 24

See Figure 9-5. The equation obtained from performing loop analysis on loop #1 is:

A) 3I1 + 7I2 - I1) + 5 V = 0
B) 3I2 + 7I2 - I1) - 5 V = 0
C) 3I2 + 7I1 - I2) + 5 V = 0
D) -3I2 + 7I2 - I1) + 5 V = 0

Question 25

What is the characteristic determinant from the following equations? 5I1 - 8I2 = 10
L0I1 + 5I2 = 20

A) 10
B) 55
C) 105
D) -90

Question 26

Which of the following terms describes the voltage across the 7 Ω resistor when using mesh analysis?

A) 7 Ω) I₂
B) 7 Ω) I₁ + I₂
C) 7 Ω) I₁
D) 7 Ω) I₁ - I₂

Question 27

A branch is a path that connects:

A) two components
B) two multiple loop circuits
C) two loops
D) two nodes

Question 28

In Figure what value of R will result in a balanced bridge?

A) 60 Ω
B) 300 Ω
C) 30 Ω
D) 3 Ω

Question 29

Solve for I1 and I2 in the following equation: 100I1 + 30I2 = 30
75I1 - 45I2 = 20

A) I1 = 28.9 mA, I2 = 3.7 mA
B) I1 = 0.289 A, I2 = 0.037 A
C) I1 = 0.037 A, I2 = 0.368 A
D) I1 = 0.289 A, I2 = -0.037 A

Question 30

Given the circuit in Figure , find the approximate current flow through the 500 Ω resistor.

A) 1.69 mA
B) 3.47 mA
C) 8.63 mA
D) 5.16 mA

Question 31

See Figure 9-4. If nodal analysis were to be used to solve for unknown voltages in this circuit, how many nodes would be needed including the reference node)?

A) 1
B) 2
C) 3
D) 4

Question 32

The node voltage method for the Bridged-T circuit:

A) creates a source node and a reference node.
B) results in two unknowns.
C) results in two equations.
D) all of the above
E) none of the above

Question 33

How many general steps are used in applying the branch current method?

A) 5
B) 4
C) 1
D) 3

Question 34

A branch current is an current through a branch, whereas: loop currents are .

A) actual, circuit dependent
B) assumed, mathematical quantities
C) actual, mathematical
D) both A and B

Question 35

Given the circuit in Figure , find the approximate voltage drop across the 68 Ω resistor.

A) 1.36 V
B) 14.28 V
C) 11.69 V
D) 12.92 V

Question 36

If the branch current method is used, which equation describes loop 1?

A) 0 = -5 V - 3 Ω)I₁ + 7 Ω)I₂
B) 0 = +5 V - 3 Ω)I₁ + 7 Ω)I₂
C) 0 = +5 V + 3 Ω)I₁ - 7 Ω)I₂
D) 0 = -5 V - 3 Ω)I₁ - 7 Ω)I₂

Question 37

Which statement is true if the loop current I2 is found to be a negative number?

A) The 10 V battery and 10 Ω resistor should have been converted to a current source.
B) The determinant used to compute the current should have been third order, not second order.
C) The nodal analysis approach should have been used, not the mesh analysis approach.
D) The original direction assumed for I₂ is wrong.

Question 38

Simultaneous equations can be solved by which two methods?

A) substitution and loop
B) determinant and mesh
C) substitution and coefficient
D) substitution and determinant

Question 39

See Figure 9-5. Which equation describes node X?

A) I3 = I2 + I1
B) I1 + I2 + I3 = 0
C) -I1 - I2 - I3 = 0
D) I3 = I2 - I1