Advertisements
Advertisements
प्रश्न
An ac generator generates an emf which is given by e = 311 sin (240 πt) V. Calculate:
- frequency of the emf.
- r.m.s. value of the emf.
उत्तर
(1) Given that
e = 311 sin (240 πt) V ...(i)
∵ e = e0 sin (ωt) V ...(ii)
From equations (i) and (ii)
e0 = 311 and ωt = 240 πt
∴ ω = 240 π
f = `omega/(2pi)`
`= (240 pi)/(2pi)`
= 120 cycle/s
e0 = Peak emf of the generator = 33
∵ Peak emf = rms · emf × `sqrt2`
∴ rms = `1/sqrt2` peak emf
= 0.707 × 311 = 219.87 volts
∴ rms = 219.87 volts
(2) Given the number of turns in the primary winding is NP = 60 turns.
The number of turns in secondary winding is NS = 3000 turns.
APPEARS IN
संबंधित प्रश्न
The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4 Ω, what is the maximum current that can be drawn from the battery?
A battery of emf 10 V and internal resistance 3 Ω is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?
A storage battery of emf 8.0 V and internal resistance 0.5 Ω is being charged by a 120 V dc supply using a series resistor of 15.5 Ω. What is the terminal voltage of the battery during charging? What is the purpose of having a series resistor in the charging circuit?
A potentiometer wire of length 1.0 m has a resistance of 15 Ω. It is connected to a 5 V battery in series with a resistance of 5 Ω. Determine the emf of the primary cell which gives a balance point at 60 cm.
A rectangular conductor LMNO is placed in a uniform magnetic field of 0.5 T. The field is directed perpendicular to the plane of the conductor. When the arm MN of length of 20 cm is moved towards left with a velocity of 10 ms−1, calculate the emf induced in the arm. Given the resistance of the arm to be 5 Ω (assuming that other arms are of negligible resistance) find the value of the current in the arm.
The following figure shows an arrangement to measure the emf ε and internal resistance r of a battery. The voltmeter has a very high resistance and the ammeter also has some resistance. The voltmeter reads 1.52 V when the switch S is open. When the switch is closed, the voltmeter reading drops to 1.45 V and the ammeter reads 1.0 A. Find the emf and the internal resistance of the battery.
How many time constants will elapse before the power delivered by a battery drops to half of its maximum value in an RC circuit?
A coil of resistance 100 Ω is connected across a battery of emf 6.0 V. Assume that the heat developed in the coil is used to raise its temperature. If the heat capacity of the coil is 4.0 J K−1, how long will it take to raise the temperature of the coil by 15°C?
Find the emf of the battery shown in the figure:
A cell of emf E is connected across an external resistance R. When current 'I' is drawn from the cell, the potential difference across the electrodes of the cell drops to V. The internal resistance 'r' of the cell is ______.
