Peak and RMS values of alternating current and voltage — NEET & JEE Questions

Question 1 · difficulty L1 · recall

For a sinusoidal current i=I0 sinωt, I0 is the

• A. peak current
• B. RMS current
• C. average over a full cycle
• D. frequency

Question 2 · difficulty L1 · understanding

The RMS value of a sinusoidal current with peak I0 is

• A. sqrt(2)I0
• B. I0/sqrt(2)
• C. I0/2
• D. 2I0/π

Question 3 · difficulty L2 · understanding

The RMS value of a sinusoidal voltage with peak V0 is

• A. V0
• B. 2V0/π
• C. V0/sqrt(2)
• D. sqrt(2)V0

Question 4 · difficulty L2 · application

A 230 V AC mains rating normally refers to approximately

• A. 230 V peak
• B. 230 V peak-to-peak
• C. 230 V average over a full cycle
• D. 230 V RMS

Question 5 · difficulty L2 · understanding

For a sinusoidal alternating current with peak value $I_0$, the RMS current is

• A. $I_0/\sqrt2$
• B. $I_0/2$
• C. $\sqrt2 I_0$
• D. $2I_0$

Question 6 · difficulty L3 · application

A sinusoidal current has RMS value 5 A. Its peak value is

• A. 5sqrt(2) A
• B. 5/sqrt(2) A
• C. 10 A
• D. 2.5 A

Question 7 · difficulty L3 · application

The average value of an ideal sinusoidal current over one complete cycle is

• A. I0/√2
• B. zero
• C. 2I0/π
• D. I0

Question 8 · difficulty L3 · application

A sinusoidal AC source has peak voltage 311 V. Its RMS voltage is closest to

• A. 110 V
• B. 220 V
• C. 311 V
• D. 440 V

Question 9 · difficulty L3 · application

A sinusoidal current has RMS value 5.0 A. Its peak value is approximately

• A. 3.54 A
• B. 5.0 A
• C. 7.07 A
• D. 10.0 A

Question 10 · difficulty L4 · analysis

Why is RMS current useful for power calculations in a resistor?

• A. It equals the largest instantaneous current
• B. It is always the arithmetic average of current
• C. It gives the same average heating as an equal DC current
• D. It makes resistance vanish