In a purely capacitive A.C circuit, the current is:
Correct answer: C. Leads the emf by 90'
- A. In phase with emf
- B. The emf by 90o
- C. Leads the emf by 90'
- D. All of the above
Explanation
In a purely capacitive AC circuit, the current lags behind the electromotive force (emf) by 90 degrees. This means that the current reaches its maximum or minimum value 90 degrees after the voltage does. This phase difference occurs because of the behavior of capacitors in AC circuits. Capacitors store and release energy over time, causing the current to lag behind the voltage. Initially, when the voltage across the capacitor increases, the capacitor charges up, and current starts to flow. However, the rate at which the current increases is limited by the capacitance of the capacitor. As a result, the current takes time to reach its maximum value, causing it to lag behind the voltage by 90 degrees in a purely capacitive AC circuit.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Alternating Current
Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
Practise Alternating Current
592 free Alternating Current MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.