We can measure d.c. by an ordinary ammeter, but not a.c. Why ?

The d.c. and a.c. both, can be measured by a hot wire instrument. Why ?

Answer the following questions : (a) In any a.c. circuit, is the applied instantaneous voltage equal to the algebraic sum of the instantaneous voltages acorss the series elements of the circuit ? Is the same true for r.m.s. voltage? (b) A capacitor is used in the primary circuit of an induction coil. (c ) An applied voltage signal consists of a superposition of a d.c. voltage and an a.c. voltage of high frequency. The circuit consists of an inductor and a capacitor in series. Show that the d.c. signal will appear across C and the a.c. signal will appear across L. (d) A choke coil in series with a lamp is connected to a d.c. line. The lamp is seen to shine brightly. Insertion of an iron core in the choke causes no change in the lamp's brightness. Predict the corresponding observation if the connection is to an a.c. line. (e) Why is choke coil needed in use of fluorescent tubes with ac mains ? Why can we not use an ordinary resistor instead of choke coil?

In the circuit shown, a 30 V d.c. source gives a current 2.0 A as recorded in the ammeter A and 30 V a.c. source of frequency 100 Hz gives a currentd 1.2 A . The inductive reactance is

The household supply voltage as measured by an a.c. voltmeter is 200 meter is 220 volts. If the frequency of a.c. Supply is 50 Hz, then the equation of the line voltage, will be

Incorrect statement are :- (a) A.C. meters can measure D.C also (b) If A.C. meter measures D.C. there scale must be linear and uniform (c) A.C. and D.C. meters are based on heating effect of current (d) A.C. meter reads rms value of current

How can we convert a galvanometer into an ammeter ?