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1) The rate of the flow of the current is equal to the electromotive force divided by resistance.

Pythagorean Theorem

Ohm’s Law

Olin’s Law

Horsepower

Ohm's Law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. In other words, the rate of flow of current (I) is equal to the electromotive force (V) divided by the resistance (R). This relationship is expressed mathematically as I = V/R. Therefore, the given statement correctly describes Ohm's Law, which explains the relationship between current, voltage, and resistance in an electrical circuit.

Explanation

Ohm's Law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. In other words, the rate of flow of current (I) is equal to the electromotive force (V) divided by the resistance (R). This relationship is expressed mathematically as I = V/R. Therefore, the given statement correctly describes Ohm's Law, which explains the relationship between current, voltage, and resistance in an electrical circuit.

2) The total voltage in a series circuit is equal to the sum of the voltages across all parts of the circuit

True

False

In a series circuit, the components are connected one after another, creating a single path for the current to flow. Since the current is the same throughout a series circuit, the voltage across each component adds up. This is because the total voltage supplied by the battery is divided among all the components in the circuit. Therefore, the statement that the total voltage in a series circuit is equal to the sum of the voltages across all parts of the circuit is true.

Explanation

In a series circuit, the components are connected one after another, creating a single path for the current to flow. Since the current is the same throughout a series circuit, the voltage across each component adds up. This is because the total voltage supplied by the battery is divided among all the components in the circuit. Therefore, the statement that the total voltage in a series circuit is equal to the sum of the voltages across all parts of the circuit is true.

3) An appliance is rated at 1,200 watts, and is connected to 120 volts. How much current will it draw?

1A

10A

100A

Cannot be determined from the information given

The current drawn by an appliance can be calculated using Ohm's Law, which states that current (I) is equal to power (P) divided by voltage (V). In this case, the power rating of the appliance is given as 1,200 watts and the voltage is 120 volts. By dividing 1,200 watts by 120 volts, we can calculate that the current drawn by the appliance is 10 amperes (A). Therefore, the correct answer is 10A.

Explanation

The current drawn by an appliance can be calculated using Ohm's Law, which states that current (I) is equal to power (P) divided by voltage (V). In this case, the power rating of the appliance is given as 1,200 watts and the voltage is 120 volts. By dividing 1,200 watts by 120 volts, we can calculate that the current drawn by the appliance is 10 amperes (A). Therefore, the correct answer is 10A.

4) The Ohm's Law pie chart contains four quadrants. They represent

Volts, amps, Ohms, horsepower

Volts, amps, Ohms, impedance

Watts, amps, Ohms, inductance

Volts, amps, Ohms, watts

The Ohm's Law pie chart contains four quadrants that represent volts, amps, Ohms, and watts. This is because Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor. Therefore, volts represent the voltage, amps represent the current, Ohms represent the resistance, and watts represent the power.

Explanation

The Ohm's Law pie chart contains four quadrants that represent volts, amps, Ohms, and watts. This is because Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor. Therefore, volts represent the voltage, amps represent the current, Ohms represent the resistance, and watts represent the power.

5) A 12v circuit draws a current of 5 amperes. What is the power consumption (watts)?

2.4 watts

60 watts

.416 watts

None of the above

P = E x I, Power (watts) = Volts x Amperes

Explanation

P = E x I, Power (watts) = Volts x Amperes

6) The total resistance of a series circuit can never be greater that the largest resistance of a single point on a circuit.

True

False

The total resistance of a series circuit is equal to the sum of the resistances of all the parts of the circuit

Explanation

The total resistance of a series circuit is equal to the sum of the resistances of all the parts of the circuit

7) A2 + B2 = C2 is also referred to as:

Pylorus’ Theorem.

Pythagorean Theorem.

An isosceles triangle.

A rhombus.

The equation A2 + B2 = C2 is known as the Pythagorean Theorem. It states that in a right-angled triangle, the square of the length of the hypotenuse (C) is equal to the sum of the squares of the other two sides (A and B). This theorem is fundamental in geometry and is used to calculate unknown side lengths or determine if a triangle is a right-angled triangle. The other options, Pylorus’ Theorem, an isosceles triangle, and a rhombus, are unrelated to this equation and do not represent the concept described.

Explanation

The equation A2 + B2 = C2 is known as the Pythagorean Theorem. It states that in a right-angled triangle, the square of the length of the hypotenuse (C) is equal to the sum of the squares of the other two sides (A and B). This theorem is fundamental in geometry and is used to calculate unknown side lengths or determine if a triangle is a right-angled triangle. The other options, Pylorus’ Theorem, an isosceles triangle, and a rhombus, are unrelated to this equation and do not represent the concept described.

8) Three resistors in parallel. Each has a value of 12 Ohms resistance. What is the total resistance of the circuit?

36 Ohms

4 Ohms

40 Ohms

3.6 Ohms

According to the formula RT= R/N, if we divide the resistance of any one of the resistors by the number of resistors (3), we will find the total resistance of the circuit.

Explanation

According to the formula RT= R/N, if we divide the resistance of any one of the resistors by the number of resistors (3), we will find the total resistance of the circuit.

9) A resistor has a color code of yellow, violet, red, and gold. What is the value of the resistor, including the tolerance?

4,700 Ohms, +/- 5%

4.7 Ohms, +/- 10%

2,400 Ohms, +/- 5%

24 Ohms, +/- 10%

3,300 Ohms, +/- 5%

First digit 4 (yellow), second digit 7 (violet), followed by 2 (red) zeros: 4,700 Ohms. Gold signifies that the tolerance is ±5%, so the real resistance could lie anywhere between 4,465 and 4,935 Ohms.

Explanation

First digit 4 (yellow), second digit 7 (violet), followed by 2 (red) zeros: 4,700 Ohms. Gold signifies that the tolerance is ±5%, so the real resistance could lie anywhere between 4,465 and 4,935 Ohms.

10) When installing a conduit with control circuits that extend beyond the walls of a residence (for example to an intercom at a gate, or to a camera on a pole in the back yard), the proper depth for burial of cables is

6 in

18 in

24 in

3 ft

NEC, Table 300.5

Explanation

NEC, Table 300.5

11) In a parallel circuit, the total resistance is _________________ the resistance of any branch

Always greater than

Always equal to

Always less than

Never less than

In a parallel circuit, the total resistance is always less than the resistance of any branch. This is because in a parallel circuit, the current has multiple paths to flow through. As a result, the total resistance decreases as the number of branches increases. This can be explained using Ohm's Law, which states that resistance is inversely proportional to current. Therefore, with more branches, the current is divided among them, resulting in a lower total resistance.

Explanation

In a parallel circuit, the total resistance is always less than the resistance of any branch. This is because in a parallel circuit, the current has multiple paths to flow through. As a result, the total resistance decreases as the number of branches increases. This can be explained using Ohm's Law, which states that resistance is inversely proportional to current. Therefore, with more branches, the current is divided among them, resulting in a lower total resistance.

12) The total resistance of a number of equal resistors in parallel is __________ the resistance of one resistor divided by the number of resistors.

Less than

Greater than

Equal to

The sum of

When resistors are connected in parallel, the total resistance is equal to the resistance of one resistor divided by the number of resistors. This is because in a parallel circuit, the voltage across each resistor is the same, so the current through each resistor is inversely proportional to its resistance. Therefore, the total resistance decreases as more resistors are added in parallel, resulting in a value equal to the resistance of one resistor divided by the number of resistors.

Explanation

When resistors are connected in parallel, the total resistance is equal to the resistance of one resistor divided by the number of resistors. This is because in a parallel circuit, the voltage across each resistor is the same, so the current through each resistor is inversely proportional to its resistance. Therefore, the total resistance decreases as more resistors are added in parallel, resulting in a value equal to the resistance of one resistor divided by the number of resistors.

13) A 4 in. x 1 ¼ in. round or octagonal box has a capacity of 12.5 cubic inches. How many number 18 gauge red fire alarm wires can the box hold?

4

8

16

12

National Electrical Code Tables

Explanation

National Electrical Code Tables

14) The circumference of a circle can be calculated using the following formula:

3.1416 x 2 x radius

3.1416 x radius2

Radius x square root of 3.1416

A2 + B2 = C2

The correct answer is 3.1416 x 2 x radius because the formula for calculating the circumference of a circle is 2πr, where π is approximately equal to 3.1416 and r is the radius of the circle. Multiplying 2 by π and then by the radius gives us the circumference of the circle.

Explanation

The correct answer is 3.1416 x 2 x radius because the formula for calculating the circumference of a circle is 2πr, where π is approximately equal to 3.1416 and r is the radius of the circle. Multiplying 2 by π and then by the radius gives us the circumference of the circle.

15) A half-inch, trade-size EMT conduit has a maximum fill capacity of ________ % with _________ wire(s).

31%, 4; 40%, 2; and 53%, 1

31%, 2; 40%, 3; and 53%, 1

40%, 3 or more; 50%, 2; and 60%, 1

53%, 1; 40%, more than 2; and 31%, 2

NEC, Table 1, Chapter 9

Explanation

NEC, Table 1, Chapter 9