FCC Technician Class Exam Study Guide - 2014-2018/Subelement T5 Group D

Ohm's Law: formulas and usage

Question 1

 * What formula is used to calculate current in a circuit?
 * A. Current (I) equals voltage (E) multiplied by resistance (R)
 * B. Current (I) equals voltage (E) divided by resistance (R)
 * C. Current (I) equals voltage (E) added to resistance (R)
 * D. Current (I) equals voltage (E) minus resistance (R)

The correct answer is B.

Question 2

 * What formula is used to calculate voltage in a circuit?
 * A. Voltage (E) equals current (I) multiplied by resistance (R)
 * B. Voltage (E) equals current (I) divided by resistance (R)
 * C. Voltage (E) equals current (I) added to resistance (R)
 * D. Voltage (E) equals current (I) minus resistance (R)

The correct answer is A.

Question 3

 * What formula is used to calculate resistance in a circuit?
 * A. Resistance (R) equals voltage (E) multiplied by current (I)
 * B. Resistance (R) equals voltage (E) divided by current (I)
 * C. Resistance (R) equals voltage (E) added to current (I)
 * D. Resistance (R) equals voltage (E) minus current (I)

The correct answer is B.

Question 4

 * What is the resistance of a circuit in which a current of 3 amperes flows through a resistor connected to 90 volts?
 * A. 3 ohms
 * B. 30 ohms
 * C. 93 ohms
 * D. 270 ohms

The correct answer is B.

Question 5
What is the resistance in a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
 * A. 18 ohms
 * B. 0.125 ohms
 * C. 8 ohms
 * D. 13.5 ohms

The correct answer is C.

Question 6

 * What is the resistance of a circuit that draws 4 amperes from a 12-volt source?
 * A. 3 ohms
 * B. 16 ohms
 * C. 48 ohms
 * D. 8 Ohms

The correct answer is A.

Question 7

 * What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms?
 * A. 9600 amperes
 * B. 200 amperes
 * C. 0.667 amperes
 * D. 1.5 amperes

The correct answer is D.

Question 8

 * What is the current flowing through a 100-ohm resistor connected across 200 volts?
 * A. 20,000 amperes
 * B. 0.5 amperes
 * C. 2 amperes
 * D. 100 amperes

The correct answer is C.

Question 9

 * What is the current flowing through a 24-ohm resistor connected across 240 volts?
 * A. 24,000 amperes
 * B. 0.1 amperes
 * C. 10 amperes
 * D. 216 amperes

The correct answer is C.

Question 10

 * What is the voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it?
 * A. 1 volt
 * B. 0.25 volts
 * C. 2.5 volts
 * D. 1.5 volts

The correct answer is A.

Question 11

 * What is the voltage across a 10-ohm resistor if a current of 1 ampere flows through it?
 * A. 1 volt
 * B. 10 volts
 * C. 11 volts
 * D. 9 volts

The correct answer is B.

Question 12

 * What is the voltage across a 10-ohm resistor if a current of 2 amperes flows through it?
 * A. 8 volts
 * B. 0.2 volts
 * C. 12 volts
 * D. 20 volts

The correct answer is D.