Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainPhysicsAlternating Current

An electric current consists of a steady direct current (DC) component I₀ and a sinusoidal alternating current (AC) component I₁ ( t) . If the overall root mean square (RMS) value of this mixed current is measured to be 3 times the DC component I₀ , the ratio of the peak value of the alternating current to the direct current ( I₁ I₀ ) is

Options

  1. A2
  2. B2
  3. C4
  4. D0.5

Correct answer

B. 2

Step-by-step solution

The instantaneous current is given by i(t) = I₀ + I₁ ( t) . The mean square value of the current over a complete cycle is: i^2 = (I₀ + I₁ ( t))^2 i^2 = I₀^2 + I₁^2 ^2( t) + 2I₀ I₁ ( t) Since the average value of ( t) over a full cycle is zero and the average value of ^2( t) is 1 2 , we get: I_ rms ^2 = I₀^2 + I₁^2 2 It is given that I_ rms = 3 I₀ . Substituting this into the equation: ( 3 I₀)^2 = I₀^2 + I₁^2 2 3 I₀^2 = I₀^2 + I₁^2 2 2 I₀^2 = I₁^2 2 I₁^2 = 4 I₀^2 Taking the square root of both sides: I₁ I₀ = 2 Answe

Practice Alternating Current on Quantrex Academy →

More from Alternating Current

Consider a circuit consisting of a capacitor of capacitance C and a coil with N turns per unit length, cross sectional area S and length d , where d^2 S . There is another coil of 2026An LCR series circuit driven with E_ rms = 90 V at frequency f_d = 30 Hz has resistance R = 80 , , an inductance with inductive reactance X_L = 20.0 , and capacitance with capacitiv 2026A series LCR circuit with R = 20 , L = 1.6 H and C = 40 F is connected to a variable frequency a.c. source. The inductive reactance at resonant frequency is _______ . 2026An a.c. source of angular frequency is connected across a resistor R and a capacitor C in series. The current is observed as I . Now the frequency of the source is changed to /4 , 2026An inductor of 10 mH, capacitor of 0.1 F and a resistor of 100 are connected in series across an a.c power supply 220 V, 70 Hz. The power factor of the given circuit is 0.5 . The d 2026The figure given below shows an LCR series circuit with two switches S₁ and S₂ . When switch S₁ is closed keeping S₂ open, the phase difference ( ) between the current and source v 2026An inductor stores 16 J of magnetic field energy and dissipates 32 W of thermal energy due to its resistance when an a.c. current of 2 A (rms) and frequency 50 Hz flows through it. 2026The electric current in the circuit is given as i=i_ o (t / T) . The r.m.s current for the period t=0 to t=T is _ _ _ _ . 2026 Full Alternating Current list All JEE Main PYQs