When an alternating current flows through an ohmic resistor, what percentage of electrical power is transformed into heat__________?
Show answer Hide answer
Answer: B. true power
Explanation
Ohmic resistors possess electrical resistance that converts electrical energy into thermal heat. True power represents the actual working energy dissipated within the resistive material. Reactive power is not converted into heat because it is stored and returned to the source. Ohm's law and Joule's law govern the conversion of electrical energy into thermal dissipation. Resistors do not store energy in magnetic or electric fields like inductors and capacitors. Power factor in a purely resistive circuit is equal to one hundred percent.
Electric space heaters convert one hundred percent of true electrical power into useful heat. Braking resistors in industrial motor drives safely dissipate regenerated kinetic energy as heat. Resistor power ratings ensure components can dissipate true power without suffering thermal damage. Apparent power includes both true power and reactive power components combined together. Reactive power describes energy oscillating between the source and reactive circuit components. Option D is incorrect because true power accurately identifies the energy transformation process.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. The time constant of an electrical circuit represents the duration in seconds following voltage application required for each___________?
Show answer Hide answer
Answer: C. 63% of maximum value
The mathematical exponential growth equation reaches sixty-three percent at one time constant. Charging a capacitor through a resistor follows this predictable exponential voltage curve. One time constant is defined as t...
Q2. Which circuit component acts to resist sudden alterations in circuit voltage ?
Show answer Hide answer
Answer: B. Capacitance
Capacitors store electrical energy inside electrostatic fields established across their plates. Changing the voltage across a capacitor requires supplying charging current over a finite duration. This inherent storage pr...
Q3. What is the formula used to calculate the time constant of a series R-C circuit____________?
Show answer Hide answer
Answer: C. RC
The time constant formula for a series resistor-capacitor circuit is resistance multiplied by capacitance. Resistance is measured in ohms and capacitance is measured in farads to yield seconds. This product determines ho...
Q4. In what specific waveform are the r.m.s. value and the mean value entirely identical___________?
Show answer Hide answer
Answer: C. square wave
Square waves have a constant amplitude that never varies throughout their high and low states. Because the magnitude is always constant, the root-mean-square value equals the mean value. Both mathematical calculations yi...
Q5. How can the resonance frequency magnitude be adjusted in an R-L-C series resonant circuit__________?
Show answer Hide answer
Answer: D. LorC
Resonant frequency depends strictly on the square root of the product of inductance and capacitance. Altering either inductance or capacitance changes the frequency where reactances cancel out. Resistance affects bandwid...
Q6. Why are wire-wound resistors generally unsuited for high-frequency applications_______?
Show answer Hide answer
Answer: D. exhibit unwanted inductive and capacitive effects
Wire-wound resistors are constructed by winding resistive wire into helical coil shapes. Coiled wire naturally creates significant parasitic inductance and inter-turn capacitive effects. These unwanted reactive component...