Advertisements
Advertisements
प्रश्न
State the average or mean value of an alternating emf? Obtain the expression for it.
Advertisements
उत्तर
- average or mean value of A.C. is the average of all values of the voltage (or current) over the one-half cycle.
- Since the average value of sin ωt over a cycle is zero, the average value over a full cycle is always zero.
- Hence, the mean value of AC over a cycle has no significance and the mean value of AC is defined as the average over half cycle.
- The average value of sinθ in the range 0c to πc is given as,
(sin θ) = `(int_0^pi sin theta "d"theta)/(int_0^pi "d"theta) = ([-cos theta]_0^pi)/([theta]_0^pi) = 2/pi = 0.637` - Therefore, average value of emf = 0.637 × peak value i.e., eav = 0.637 e0
संबंधित प्रश्न
Find the capacity of a capacitor which when put in series with a 10Ω resistor makes the power factor equal to 0.5. Assume an 80V-100Hz AC supply.
Find the time required for a 50 Hz alternating current to change its value from zero to the rms value.
If the effective current in a 50 cycle AC circuit is 5 A, what is the peak value of current? What is the current 1/600 after if was zero?
What is the relation between average current and rms current over half cycle?
Alternating current cannot be measured by D.C. ammeter because ____________.
An alternating voltage e = `200sqrt2` sin(100 t) volt is connected to a 1 µF capacitor through a.c. ammeter. The reading of the ammeter is ______
The rms value of current in a 50 Hz AC circuit is 6 A. The average value of AC current over a cycle is ____________.
An alternating voltage is given by E = 100 sin`(omega + pi/6)"V"`. The voltage will be maximum for the first time when is ______. [T = periodic time]
In half-wave rectifier, the RMS value of A.C. component of the wave is ____________.
Instrument which measures alternating current is based on ____________.
A 60 `Omega` electric heater is connected to a 200 V, 50 Hz mains supply. The peak value of electric current flowing in the circuit is approximately ______.
What is the r.m.s. value of an alternating current which when passed through a resistor produces heat which is four times of that produced by a direct current of 3 ampere in the same resistor?
A 25 watt lamp is connected to a.c. potential of peak value 100 V. Calculate the rms value of the current.
An alternating voltage is given by e = 8sin628.4t. Find
- peak value of e.m.f.
- frequency or e.m.f.
- instantaneous value of e.m.f. at time t = 10. ms
The instantaneous voltage through a circuit of impedance \[10\Omega\] is V = 40sin \[(50\pi t).\] The effective value of current is ______.
A 10 µF capacitor is connected to a 210 V, 50 Hz source as shown in figure. The peak current in the circuit is nearly (π = 3.14):
An LCR circuit contains resistance of 110 Q and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45°. If on the other hand, only inductor is removed the current leads by 45° with the applied voltage. The rms current flowing in the circuit will be ______.
The instantaneous value of current in an a.c. circuit is I = `2 sin [100 pi t + pi/3]` A. The curent wil be maximum for the first time at ______.
(sin 90° = 1)
An alternating e.m.f. is given by e = e0 sin ωt. In what time the e.m.f. will have value `e_0/sqrt 2`, if ‘e’ starts from zero?
`(sin 45^circ = 1/sqrt 2)`
