CBT Electronic & Electrical Fundamentals 1 — Questions and Answers
Question 1: What does Ohm’s Law state?
- Voltage equals current plus resistance
- Voltage equals current divided by resistance
- Voltage equals current times resistance (Correct answer)
- Voltage equals resistance minus current
Correct answer: Voltage equals current times resistance
Ohm's Law is a fundamental principle in electrical engineering that describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. It states that the voltage across a conductor is directly proportional to the current flowing through it, with the constant of proportionality being the resistance. This is commonly expressed by the formula V = I × R.
Question 2: Which unit is used to measure electrical resistance?
- Ampere
- Volt
- Watt
- Ohm (Correct answer)
Correct answer: Ohm
The Ohm (Ω) is the SI derived unit of electrical resistance, named after German physicist Georg Ohm. Resistance is a measure of the opposition to the flow of electric current in an electrical circuit. A higher resistance means less current will flow for a given voltage.
Question 3: What is the primary function of a capacitor in an AC circuit?
- Increase current flow
- Store and release electrical energy (Correct answer)
- Convert voltage to resistance
- Reduce inductance
Correct answer: Store and release electrical energy
A capacitor is a passive electronic component that stores electrical energy in an electric field between two conductive plates separated by a dielectric. In an AC circuit, capacitors repeatedly charge and discharge, allowing them to store and release this energy. They are commonly used for filtering, timing, and energy storage applications, blocking DC while passing AC.
Question 4: Which component resists the flow of current in a circuit?
- Capacitor
- Resistor (Correct answer)
- Diode
- Transistor
Correct answer: Resistor
A resistor is a passive two-terminal electrical component specifically designed to resist the flow of electric current in a circuit. It introduces a controlled amount of electrical resistance, converting electrical energy into heat. Resistors are used to limit current, divide voltage, and terminate transmission lines, among other functions.
Question 5: What is the result of connecting resistors in series?
- Current increases
- Voltage drops to zero
- Total resistance increases (Correct answer)
- Resistance cancels out
Correct answer: Total resistance increases
When resistors are connected in series, their individual resistances add up to form a larger total resistance. This means that the equivalent resistance of the series combination is the sum of all the individual resistances. This configuration effectively increases the overall opposition to current flow in the circuit.
Question 6: In a DC circuit, what does the power formula P = V × I represent?
- Power is current divided by voltage
- Power equals voltage times current (Correct answer)
- Power is resistance minus current
- Power equals voltage divided by resistance
Correct answer: Power equals voltage times current
In a DC circuit, the power (P) dissipated by a component or circuit is calculated by multiplying the voltage (V) across it by the current (I) flowing through it. This fundamental formula, P = V × I, is crucial for determining the rate at which electrical energy is consumed or converted in a circuit. It is a cornerstone of electrical engineering calculations.
CBT Electronic & Electrical Fundamentals 1
What does Ohm’s Law state?