Advertisements
Advertisements
Question
The AC voltage across a resistance can be measured using
Options
a potentiometer
a hot-wire voltmeter
a moving-magnet galvanometer
Advertisements
Solution
a hot-wire voltmeter
Only a hot-wire voltmeter can be used to measure an AC voltage across a resistor.
APPEARS IN
RELATED QUESTIONS
A current i1 = i0 sin ωt passes through a resistor of resistance R. How much thermal energy is produced in one time period? A current i2 = −i0 sin ωt passes through the resistor. How much thermal energy is produced in one time period? If i1 and i2 both pass through the resistor simultaneously, how much thermal energy is produced? Is the principle of superposition obeyed in this case?
A transformer is designed to convert an AC voltage of 220 V to an AC voltage of 12 V. If the input terminals are connected to a DC voltage of 220 V, the transformer usually burns. Explain.
A capacitor acts as an infinite resistance for ______.
The peak voltage of a 220 V AC source is
Suppose the initial charge on the capacitor is 6 mC. What is the total energy stored in the circuit initially? What is the total energy at later time?
Average power supplied to a capacitor over one complete cycle is ______.
If circuit containing capacitance only, the current ______.
A.C. power is transmitted from a power house at a high voltage as ______.
When an ac voltage of 220 V is applied to the capacitor C, then ______.
A device ‘X’ is connected to an a.c source. The variation of voltage, current and power in one complete cycle is shown in figure.
- Which curve shows power consumption over a full cycle?
- What is the average power consumption over a cycle?
- Identify the device ‘X’.
Define Capacitive reactance.
An a.c. source generating a voltage ε = ε0 sin ωt is connected to a capacitor of capacitance C. Find the expression for the current I flowing through it. Plot a graph of ε and I versus ωt to show that the current is ahead of the voltage by π/2.
A resistor of 50 Ω, a capacitor of `(25/pi)` µF and an inductor of `(4/pi)` H are connected in series across an ac source whose voltage (in volts) is given by V = 70 sin (100 πt). Calculate:
- the net reactance of the circuit
- the impedance of the circuit
- the effective value of current in the circuit.
A 40 µF capacitor is connected to a 200 V. 50 Hz ac supply. The rms value of the current on the circuit is, nearly ______.
In an ac circuit an alternating voltage e = 200\[\sqrt 2\] sin100t volts is connected to capacitor of capacity 1 µF. The r.m.s. value of the current in the circuit is ______.
The resistance of a coil for d.c. is 5 Ω. In a.c., the resistance will ______.
