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The current in a coil changes from 50A to 10A in 0.1 second. The self inductance of the coil is 20H. The induced e.m.f. in the coil is ______.
Concept: Inductance >> Self Inductance
Discuss the composition of two S.H.M.s along the same path having same period. Find the resultant amplitude and intial phase.
Concept: LC Oscillations
Obtain an expression for average power dissipated in a purely resistive A.C. circult.
Concept: Power in AC Circuit
Two diametrically opposite points of a metal ring are connected to two terminals of the left gap of meter bridge. The resistance of 11 Ω is connected in right gap. If null point is obtained at a distance of 45 cm from the left end, find the resistance of metal ring.
Concept: Meter Bridge
An unknown resistance is placed in the left gap and resistance of 50 ohm is placed in the right gap of a meter bridge. The null point is obtained at 40 cm from the left end. Determine the unknown resistance.
Concept: Meter Bridge
When unknown resistance is determined by meter bridge, the error due to contact resistance
is minimized ______.
(A) by connecting both the resistances only in one gap.
(B) by interchanging the positions of known and unknown resistance.
(C) by using uniform wire.
(D) by obtaining the null point near the ends of the wire.
Concept: Meter Bridge
A potentiometer wire has length of 2m and resistance 10Ω. It is connected in series with resistance 990Ω and a cell of e.m.f. 2V. Calculate the potential gradient along the wire.
Concept: Meter Bridge
Explain the principle of potentiometer.
Concept: Meter Bridge
When an AC source is connected to an ideal inductor show that the average power supplied by the source over a complete cycle is zero.
Concept: Power in AC Circuit
Derive an expression for the impedance of an LCR circuit connected to an AC power supply. Draw phasor diagram.
Concept: LC Oscillations
A 15.0 μF capacitor is connected to a 220 V, 50 Hz source. Find the capacitive reactance and the current (rms and peak) in the circuit. If the frequency is doubled, what will happen to the capacitive reactance and the current?
Concept: Values of Alternating Current
A 25 μF capacitor, a 0.10 H inductor, and a 25Ω resistor are connected in series with an AC source whose emf is given by e = 310 sin 314 t (volt). What is the frequency, reactance, impedance, current, and phase angle of the circuit?
Concept: Power in AC Circuit
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?
Concept: Values of Alternating Current
State the average or mean value of an alternating emf? Obtain the expression for it.
Concept: Values of Alternating Current
Explain the term capacitive reactance. State its unit and dimensions.
Concept: Phasors
An alternating emf of 230V, 50Hz is connected across a pure ohmic resistance of 50Ω. Find (1) the current (2) equations for instantaneous values of current and voltage.
Concept: Phasors
A 100 Ω resistor is connected to a 220 V, 50 Hz ac supply.
- What is the rms value of current in the circuit?
- What is the net power consumed over a full cycle?
Concept: AC Voltage Applied to a Resistor
Define Capacitive reactance.
Concept: AC Voltage Applied to a Capacitor
Define Impedance.
Concept: AC Voltage Applied to a Series LCR Circuit
