Home
Class 12
PHYSICS
Current in an ac circuit is given by I= ...

Current in an ac circuit is given by `I= 3 sin omega t + 4 cos omega t, ` then

A

rms value of current is 5A.

B

mean value of this current in any one half period will be `(6//pi)`.

C

If voltage applied is `V=V_(m) sin omega t`, then the circuit may be containing resistance and capacitance only.

D

If voltage applied is `V=V_(m) sin omega t`, then the circuit may be contain resostamce and inductance only.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the given current equation in an AC circuit: \[ I = 3 \sin(\omega t) + 4 \cos(\omega t) \] We will find the peak current, RMS value, average current, and phase difference step by step. ### Step 1: Combine the Sine and Cosine Terms We can express the current in a single trigonometric function using the following identity: \[ I = R \sin(\omega t + \phi) \] Where \( R \) is the resultant amplitude and \( \phi \) is the phase angle. To find \( R \) and \( \phi \), we can use the following relationships: - \( R = \sqrt{A^2 + B^2} \) - \( \tan(\phi) = \frac{B}{A} \) Here, \( A = 3 \) and \( B = 4 \). ### Step 2: Calculate the Resultant Amplitude \( R \) Using the formula for \( R \): \[ R = \sqrt{3^2 + 4^2} = \sqrt{9 + 16} = \sqrt{25} = 5 \] ### Step 3: Calculate the Phase Angle \( \phi \) Using the tangent formula: \[ \tan(\phi) = \frac{4}{3} \] To find \( \phi \): \[ \phi = \tan^{-1}\left(\frac{4}{3}\right) \] ### Step 4: Calculate the RMS Value \( I_{RMS} \) The RMS value for an AC current is given by: \[ I_{RMS} = \frac{I_0}{\sqrt{2}} \] Where \( I_0 \) is the peak current (which we found to be \( R = 5 \)): \[ I_{RMS} = \frac{5}{\sqrt{2}} \, \text{A} \] ### Step 5: Calculate the Average Current \( I_{avg} \) The average current over one complete cycle is given by: \[ I_{avg} = \frac{I_0}{\pi} \] Substituting \( I_0 = 5 \): \[ I_{avg} = \frac{5}{\pi} \, \text{A} \] ### Step 6: Determine the Phase Difference \( \phi \) From our earlier calculation, we have: \[ \phi = \tan^{-1}\left(\frac{4}{3}\right) \approx 53^\circ \] ### Summary of Results - Peak Current \( I_0 = 5 \, \text{A} \) - RMS Current \( I_{RMS} = \frac{5}{\sqrt{2}} \, \text{A} \) - Average Current \( I_{avg} = \frac{5}{\pi} \, \text{A} \) - Phase Difference \( \phi \approx 53^\circ \)

To solve the problem, we need to analyze the given current equation in an AC circuit: \[ I = 3 \sin(\omega t) + 4 \cos(\omega t) \] We will find the peak current, RMS value, average current, and phase difference step by step. ### Step 1: Combine the Sine and Cosine Terms We can express the current in a single trigonometric function using the following identity: ...
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • ALTERNATING CURRENT

    CENGAGE PHYSICS|Exercise Exercises Multiple Correct|5 Videos
  • ALTERNATING CURRENT

    CENGAGE PHYSICS|Exercise Exercises Assertion-reasoning|7 Videos
  • ALTERNATING CURRENT

    CENGAGE PHYSICS|Exercise Exercises Subjective|15 Videos
  • OSCILLATIONS

    CENGAGE PHYSICS|Exercise QUESTION BANK|39 Videos
  • ATOMIC PHYSICS

    CENGAGE PHYSICS|Exercise ddp.4.3|15 Videos

Similar Questions

Explore conceptually related problems

The potential diffeence V across and the current 1 following throgh an instrument in an AC circuit given by : V = 5 cos omega t volt I = 2 cos omega t volt The power dissipated in the instrument is :

The voltage and current in an a.c. circuit are given by E = 300 sin (omega t + pi//2) and I = 5 sin omega t . What is power factor of the circuit and power dissipated in each cycle ?

Knowledge Check

  • If an alternating current is given by i = a sin ( omega t) + b cos ( omega t), then RMS value of current is :-

    A
    `a/sqrt2+b/sqrt2`
    B
    `(a+b)/sqrt2`
    C
    `sqrt((a^2+b^2)/2)`
    D
    `(a^2+b^2)/sqrt2`
  • If emf and current in the circult is given by e= E_(0) sin omega t i=l_(0) sin (omega t- phi) Then the average power in the circuit over one cycle of ac is

    A
    `(E_(0)l_(0))/(2)`
    B
    `(E_(0)l_(0))/(2) sin phi`
    C
    `E_(0)l_(0)`
    D
    `(E_(0)l_(0))/(2) cos phi`
  • The instantaneous current in an A.C. circuit is given by I= 2 sin (omega t+theta) ampere. The r.m.s. value of the current is

    A
    2 ampere
    B
    `2sqrt(2)` ampere
    C
    `sqrt(2)` ampere
    D
    `1/(sqrt(2))` ampere
  • Similar Questions

    Explore conceptually related problems

    An AC current is given by I = I_(1) sin omega t + I_(2) cos omega t A hot wire ammeter will give a reading :

    The instantaneous values of emf and the current in a series ac circuit are - E = Eo Sin omega t and l = lo sin (omega t + pi //3) respectively, then it is

    If the instantaneous current in a circuit is given by I = 20 cos (omega t + phi) A , the rms value of the current is

    The potential difference V across and the current I flowing through an instrument in an AC circuit are given by: V=5 cos omega t volt I=2 sin omega t Amp.

    The displacement of an oscillator is given by x=a sin omega t+b cos omega t where a, b and omega , are constant. Then -