Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202117 MarchMorning Shift
Exam
JEE Main
Year
2021
Date
17 March
Shift
Morning Shift
Subject
Physics
Chapter
Alternating Current

JEE Main 2021 · 17 March · Morning Shift · Physics · Alternating Current

An AC current is given by I = I _ 1 sin + I _ 2 cos . A hot wire...

An ACAC current is given by I=I1sin\omegat+I2cos\omegat.I = {I}_{1}sin\omegat + {I}_{2}cos\omegat .
A hot wire ammeter will give a reading:

Options

  1. AI12−I222\sqrt{\dfrac{{I}_{1}^{2} - {I}_{2}^{2}}{2}}
  2. BI12+I222\sqrt{\dfrac{{I}_{1}^{2} + {I}_{2}^{2}}{2}}
  3. CI1+I22\dfrac{{I}_{1} + {I}_{2}}{\sqrt{2}}
  4. DI1+I222\dfrac{{I}_{1} + {I}_{2}}{2\sqrt{2}}

Correct answer

B. I12+I222\sqrt{\dfrac{{I}_{1}^{2} + {I}_{2}^{2}}{2}}

Step-by-step solution

I=I1sin\omegat+I2cos\omegatI = {I}_{1}sin\omegat + {I}_{2}cos\omegat

∴I0=I12+I22∴ {I}_{0} = \sqrt{{I}_{1}^{2} + {I}_{2}^{2}}

∴Irms=I02=I12+I222∴ {I}_{rms} = \dfrac{{I}_{0}}{\sqrt{2}} = \sqrt{\dfrac{{I}_{1}^{2} + {I}_{2}^{2}}{2}}

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… JEE Advanced 2026A LCR series circuit driven with E_ rms = 90 V at frequency f_d = 30 Hz has resistance R… JEE Main 2026A series LCR circuit with R = 20\ Ω , L = 1.6 H and C = 40\ is connected to a variable… JEE Main 2026An a.c. source of angular frequency ω is connected across a resistor R and a capacitor C… JEE Main 2026An inductor of 10 mH, capacitor of 0.1\ μ F and a resistor of 100\ Ω are connected in… JEE Main 2026The figure given below shows an LCR series circuit with two switches S_1 and S_2 . When… JEE Main 2026An inductor stores 16 J of magnetic field energy and dissipates 32 W of thermal energy… JEE Main 2026The electric current in the circuit is given as i=i_ o (t / T) . The r.m.s current for… JEE Main 2026 Full Alternating Current list All JEE Main PYQs