DC Machine Fundamentals: Voltage, Current,…

Q: What is the unit of measurement for voltage?

Volt (V) — Voltage is measured in Volts, representing the potential difference.

Q: What is the unit of measurement for electric current?

Ampere (A) — Current, the flow of charge, is measured in Amperes.

Q: What is the unit of measurement for resistance?

Ohm (?) — Resistance, which opposes current flow, is measured in Ohms.

Q: Which of the following is Ohm's Law formula?

V = I * R — Ohm's Law states Voltage (V) = Current (I) * Resistance (R).

Q: If a circuit has a voltage of 12V and a resistance of 4?, what is the current flowing through it?

3 A — Using Ohm's Law (I = V/R), I = 12V/4? = 3A.

Q: What is the relationship between voltage and current in a DC circuit with constant resistance?

They are directly proportional. — Current increases proportionally with voltage for a constant resistance.

Q: What happens to the current if the resistance in a DC circuit increases, while the voltage remains constant?

The current decreases. — I = V/R; an increase in R leads to a decrease in I, assuming V is constant.

Q: In a DC machine, the armature winding's resistance is primarily determined by the:

Length and cross-sectional area of the conductors — Resistance depends on the material, length, and cross-section of the wire.

Q: What is the purpose of the armature winding in a DC machine?

To carry the generated current and produce torque. — Armature windings carry current and interact with the field to produce torque.

Q: What is back EMF in a DC motor?

The voltage generated in the armature opposing the applied voltage. — Back EMF is generated due to the rotating armature cutting magnetic flux.

Question 1 of 10

What is the unit of measurement for voltage?

Voltage is measured in Volts, representing the potential difference.

Question 2 of 10

What is the unit of measurement for electric current?

Current, the flow of charge, is measured in Amperes.

Question 3 of 10

What is the unit of measurement for resistance?

Resistance, which opposes current flow, is measured in Ohms.

Question 4 of 10

Which of the following is Ohm's Law formula?

Ohm's Law states Voltage (V) = Current (I) * Resistance (R).

Question 5 of 10

If a circuit has a voltage of 12V and a resistance of 4?, what is the current flowing through it?

Using Ohm's Law (I = V/R), I = 12V/4? = 3A.

Question 6 of 10

What is the relationship between voltage and current in a DC circuit with constant resistance?

Current increases proportionally with voltage for a constant resistance.

Question 7 of 10

What happens to the current if the resistance in a DC circuit increases, while the voltage remains constant?

I = V/R; an increase in R leads to a decrease in I, assuming V is constant.

Question 8 of 10

In a DC machine, the armature winding's resistance is primarily determined by the:

Resistance depends on the material, length, and cross-section of the wire.

Question 9 of 10

What is the purpose of the armature winding in a DC machine?

Armature windings carry current and interact with the field to produce torque.

Question 10 of 10

What is back EMF in a DC motor?

Back EMF is generated due to the rotating armature cutting magnetic flux.

DC Machine Fundamentals: Voltage, Current, Resistance Quiz