Electrical and Refrigeration Concepts

What is the formula for Ohm's Law?

• V = I * R

• I = V / R

• R = V / I

• I = R / V

Define electrical power and its unit of measurement.

• Watt (W)

• Joule (J)

• Ohm (Ω)

• Volt (V)

Explain the difference between voltage and current in an electrical circuit.

• Voltage is the speed of electrons, while current is the color of wires.

• Voltage is the potential difference between two points in a circuit, while current is the flow of electric charge.

• Voltage is the resistance in a circuit, while current is the brightness of a light bulb.

• Voltage is the flow of electric charge, while current is the potential difference between two points in a circuit.

What is the purpose of refrigeration in HVAC systems?

• To remove heat from indoor air

• To reduce the amount of oxygen in the air

• To generate electricity for the system

• To increase humidity in indoor air

Describe the basic components of a refrigeration system.

• Compressor, Condenser, Expansion Valve, Evaporator

• Fan, Heater, Thermostat, Filter

• Condenser, Heater, Expansion Valve, Evaporator

• Compressor, Filter, Expansion Valve, Evaporator

What safety precautions should be taken during electrical maintenance?

• Wear sunglasses indoors

• Use a metal ladder near live wires

• Wear appropriate PPE, ensure power is off, use insulated tools, follow lockout/tagout procedures, avoid working on energized equipment.

• Ignore warning signs and labels

Calculate the power consumed by a device with a voltage of 120V and a current of 5A.

• 300W

• 600W

• 450W

• 100W

How does electrical insulation prevent electrical hazards?

• Electrical insulation prevents electrical hazards by creating a barrier between the electrical conductor and external objects or people, reducing the risk of electric shock or short circuits.

• Electrical insulation attracts electricity towards objects or people, increasing the risk of electric shock

• Electrical insulation is not effective in preventing electrical hazards

• Electrical insulation is a conductor that enhances the flow of electricity, leading to short circuits

What are the common causes of electrical failures in appliances?

• Water damage, excessive use, incorrect voltage

• Power surges, overheating, worn out components, poor maintenance, manufacturing defects

The rate of flow of charges is called as

• Current, I

• Potential difference, V

• Resistance, R

• Power, P