220V, 50 Hz AC supply is connected across a resistor of 50 k ohms. The current at time t Seconds, assuming that it is zero at t = O, is?
Correct answer: C. 6.2 sin(314t) mA
- A. 4.4 sin(314t) mA
- B. 4.4 sin(157t) mA
- C. 6.2 sin(314t) mA
- D. 6.2 sin(157t) mA
Explanation
The correct answer is 6.2 sin(314t) mA. The root mean square voltage (VRMS) of 220V is used to find the peak voltage (Vmax), which is 220√2 volts. The peak current (Imax) is then calculated using Ohm's law, Imax = Vmax/R. Substituting the values results in Imax being 6.2 mA. The angular frequency in radians per second is given by 2πf, where the frequency (f) is 50 Hz, resulting in 314 rad/s. Thus, the expression for the current as a function of time is i = 6.2 sin(314t) mA.Other options are incorrect due to errors in amplitude or frequency. For example, options with 4.4 mA have incorrect amplitude calculations, and those with 157t have incorrect frequency calculations.
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.
More Alternating Current questions
A diode works in _ bias for first cycle of rectification.
The principle of a capacitor is based on which of the following facts?
The variation in current with time of an alternating current is shown by a sinusoidal wave in the given figure. The root mean square (rms) current for this alternating current is
The instantaneous current in a circuit is given by I = √2 sin(ωt + ∅) ampere what is the rms value of the current?
AC generators are opposite to:
Which of the following phenomenon proves that light waves are transverse waves?