FREE ESCO Electrical Questions and Answers
How much resistance must be placed in a 120-volt circuit to limit the current to 2 amps?
Explanation:
Using Ohm's Law (V = IR), rearranged to solve for resistance (R = V/I), we find that the resistance required is R = 120V / 2A = 60 ohms.
Which of the following meters must use internal power to check a load or circuit?
Explanation:
An ohmmeter measures resistance and requires an internal power source (usually a battery) to check a load or circuit. It sends a small current through the circuit under test and measures the voltage drop to determine resistance.
What is current flow?
Explanation:
Current flow refers to the movement of electric charge carriers, typically electrons, through a conductor.
What would be the result if a 24-volt, 20-ohm contactor coil was wired in series with a 24-volt, 200-ohm control relay?
Explanation:
When wired in series, the total resistance in the circuit would be 20 ohms (contactor coil) + 200 ohms (control relay) = 220 ohms. Since the voltage is fixed at 24 volts, and using Ohm's Law (V = IR), the current in the circuit would be V/R = 24V / 220Ω ≈ 0.109A. The control relay, with its higher resistance, would have a higher voltage drop across it, resulting in it operating. However, the voltage drop across the contactor coil may not be sufficient to activate it, so only the control relay would operate.
Which of the following materials would be best suited for use as a semiconductor?
Explanation:
Silicon is a widely used semiconductor material in electronic devices due to its unique properties in controlling the flow of electric current.
Like charges will:
Explanation:
According to the law of electrostatics, like charges repel each other.
Any material that will readily release electrons is called:
Explanation:
A material that readily releases electrons is known as a conductor. Conductors allow the flow of electric current due to the ease with which electrons can move through them.
Electricity can produce:
Explanation:
Electricity can produce light, heat, and magnetism. When electricity flows through a conductor, it can generate light in a bulb, heat in a resistor, and magnetism around a wire.
What is impedance?
Explanation:
Impedance refers to the total opposition to the flow of alternating current in a circuit, including both resistance and reactance.
The safety ground conductor is usually colored:
Explanation:
The safety ground conductor is typically colored green. This standard color helps to easily identify and distinguish the ground conductor in electrical wiring systems.
When testing a capacitor with an analog or digital ohmmeter, the meter should:
Explanation:
When testing a capacitor with an ohmmeter, it should initially show low resistance (near zero) as the capacitor charges. Then, it should gradually return to a high reading as the capacitor becomes fully charged, indicating that the capacitor is functioning correctly.