The r.m.s. value and mean value is the same in the case of
A. Triangular wave
B. Sine wave
C. Square wave
D. Half wave rectified sine wave
Answer: Option C
Solution (By Examveda Team)
The correct answer is Option C: Square waveLet's break down why:
Understanding RMS and Mean Values:
* RMS Value (Root Mean Square): It's the effective value of a waveform. Think of it as the DC equivalent that would produce the same heating effect in a resistor.
* Mean Value (Average Value): It's the average value of the waveform over one complete cycle.
Why Square Wave?
A square wave spends equal time at its positive peak and its negative peak (or zero, depending on the type).
* RMS: Since the power dissipated is the same whether the voltage is positive or negative (because power is proportional to voltage squared), the RMS value is simply the amplitude of the square wave.
* Mean: If the square wave alternates between a positive value (+V) and a negative value (-V) the mean value over a complete cycle is zero. If it alternates between a positive value (+V) and zero (0), the mean value is V/2. However, if we consider only the magnitude (absolute value) of the waveform, then the mean value becomes equal to the amplitude (+V). Therefore RMS is equal to the average.
Why Not the Other Options?
* Triangular Wave: The RMS and mean values are different because the waveform changes linearly, not abruptly.
* Sine Wave: The RMS value is Vm/√2 (where Vm is the peak value) and the mean value over a full cycle is zero. Mean value is zero but average value can be calculated over half a cycle.
* Half-Wave Rectified Sine Wave: Only the positive (or negative) half of the sine wave is present. The RMS and mean values are different because the waveform is not symmetrical around zero and includes a significant period of zero voltage.
It should be half wave
The r.m.s. value and mean value is the same in the case of