HVAC unit 12

If three resistance of values 3ohms, 4ohms, and 12ohms, are wired in parallel with each other, what is the total resistance of the circuit. A. 1.5ohms B. 3ohms C. 12ohms D. 19ohms

A. 1.5 Q

Which of the following statements can best be associated with inductance.. A. A magnetic field is generated when current flows through a conductor. B. A magnetic field is generated when voltage flows through a conductor. C. A voltage is generated when current flows through a conductor. D. A voltage is generated when power flows through a conductor.

A. A magnetic field is generated when current flows through a conductor.

The most common method used to measure the amperage in a circuit is too.. A. De-energize the circuit and use a clamp on ammeter to clamp around one conductor in the circuit. B. De-energize the circuit and use a clamp on ammeter to clamp around both conductors in the circuit. C. Energize the circuit and use a clamp on ammeter to clamp around one conductor in the circuit. D. Energize the circuit and use a clamp on ammeter to clamp around both conductors in the circuit.

A. De-energize the circuit and use a clamp on ammeter to clamp around one conductor in the circuit.

Which of the following represents Ohm's law? A. E = I / R B. E = R / I C. R = E / I D. I = E x R

A. E = I / R

Impedance is the total effect of what 3 electrical characteristics.. A. Resistance, inductive reactance, capacitive reactance B. Resistance, voltage, and current C. Power, inductive reactance, an capacitive reactance D. Capacitance, reactance, inductance

A. Resistance, inductive reactance, capacitive reactance

An NPN transistor is made up of.. A. one section of P-type material and one section of N-type material B. one section of P-type material and two section of N-type material C. two section of P-type material and two section of N-type material D. two section of P-type material and one section of N-type material

A. one section of P-type material and one section of N-type material

The _______ is that part of an atom that moves from one atom to another. A.Electron B. Proton C.Positron D.Neutron

A.Electron

A solenoid can be described as.. A. The electrical contacts on a switch B. A coil of wire C. An energy storing device D. A power passing device

B. A coil of wire

What is the main difference between a fuse and a circuit breaker? A. Fuses are designed to handle larger loads than circuit breakers. B. Fuses must be replaced, while circuit breakers can be reset C. Circuit breakers must be replaced, while fuses can be reset D. Fuses are designed to protect multi-pole circuits

B. Fuses must be replaced, while circuit breakers can be reset

All of the following statements are true regarding good conductors of electricity except.. A. Good conductors of electricity are also good conductors of heat. B. Good conductors of electricity pass protons from atom to atom C. Good conductors of electricity have atoms with few electrons in the outermost shell. D. Good conductors of electricity are typically metallic elements.

B. Good conductors of electricity pass protons from atom to atom

The law of charges states that.. A. Like charges attract each other and unlike charges repel each other. B. Like charges repel each other and unlike charges attract each other. C. Like charges repel each other and unlike charges repeal each other. D. Like charges attract each other and unlike charges attract each other too.

B. Like charges repel each other and unlike charges attract each other.

Voltage can be produced when a conductor passes through.. A. Vacuum B. Magnetic field C. Dielectric D. Insulator

B. Magnetic field

The unit of measurement for the charge a capacitor can store is the.. A. Volt B. Microfarad C. Ohm D. Joule

B. Microfarad

Which of the following is a correct formula for the total resistance in a series circuit? A. R(total) = R(1), x R(2) x R(3), x ... B. R(total) = R(1), + R(2) + R(3), + ... C. R(total) = R(1), - R(2) - R(3), - ... D.R(total) = R(1), / R(2) / R(3), / ...

B. R(total) = R(1), + R(2) + R(3), + ...

A residential AC power supply is often represented by a.. A. Horizontal line B. Sine wave C. Triangular shaped wave D. Set of 2 parallel lines

B. Sine wave

Two common types of capacitors are the.. A. Run and Stop B. Start and Run C. Short and Start D. Stop and Short

B. Start and Run

All of the following are required in an electric circuit except a.. A. Power source B. Switch C. Complete conductive path D. Load

B. Switch

If an atom has a net positive charge, which of the following is correct? A.The atom has lost protons. B.The atom has lost electrons C.The atom has gained protons D.The atom has gained protons

B. The atom has lost electrons

If the resistance in a 120V circuit was 40ohms what would the current be in amperes? A. 4800A B. 48A C. 4A D. 3A

C. 3A

If a step down transformer has windings with 1000 and 500 turns, what is the induced voltage at the secondary winding if 100 volts is being applied to the primary winding.. A. 200V B. 100V C. 50V D. 25V

C. 50V

If there were a current flowing of 5Amps in a 120V circuit, what would the resistance be? A. 25V B. 24V C. 600V D. 624V

C. 600V

All of the following are true regarding DC power except.. A. DC Power can created from AC power. B. A common source of DC power is batteries. C. DC power continually reverses its polarity. D. The term DC stands for Direct Current.

C. DC power continually reverses its polarity.

The opposition to current flow in a circuit is commonly referred to as.. A. Capacitance B. Inductance C. Resistance D. Reactance

C. Resistance

undersized wires can cause.. A. Voltage surges, tripped circuit breakers, and overheating B. Voltage surges, decreased resistance, and overheating C. Voltage drops, tripped circuit breakers, and overheating D. Voltage drops, decreased resistance, and overheating

C. Voltage drops, tripped circuit breakers, and overheating

Electrical Power is measure in.. A. Amperes B. Volts C. Watts D. Ohms

C. Watts

If three resistance of values 3ohms, 4ohms, and 12ohms are wired in series with each other, what is the total resistance of the circuit. A. 1.5ohms B. 3ohms C. 12ohms D. 19ohms

D. 19 Q

Which of the following statements is true regarding circuit protection devices? A. GFCIs are intended for use in wet or potentially wet locations. B. Fuses must be rated at an amperage that is lower than the expected current draw of a circuit C. Circuit breakers must be rated at an amperage that is lower then the expected current draw of a circuit D. Fuses and circuit breakers are intended to protect the device being controlled.

D. Fuses and circuit breakers are intended to protect the device being controlled.

The nucleus of an atom contains which particles? A.Electrons and neutrons B.Positrons and protons C.Electrons and positrons D.Neutrons and protons

D. Neutrons and Protons

Which of the following represents an accurate formula for power? A. P = I / R B. P = R x I C. P = E / I D. P = E x I

D. P = E x I

diode is a solid state circuit component that. A. allows current to flow when reversed biased B. prevent current flow when forward biased C. prevents current flow in both directions D. allows current to flow in only one direction

D. allows current to flow in only one direction