In a series LCR circuit, obtain the conditions under which
(i) the impedance of the circuit is minimum, and
(ii) wattless current flows in the circuit.
In series R-L-C circuit, quality factor can be improved by
(a) decreasing L
(b) increasing C
(c) decreasing R
(d) decreasing R & L
An ac voltage V = V₀ sin ωt is applied to a pure inductor L. Obtain an expression for the current in the circuit. Prove that the average power supplied to an inductor over one complete cycle is zero.
In highly inductive load circuit, it is more dangerous when
(a) we close the switch
(b) open the switch
(c) increasing the resistance
(d) decreasing the resistance
State which of the two a capacitor or an inductor, tends to become SHORT when the frequency of the applied alternating voltage has a high value.
A lamp is connected in series with a capacitor. Predict your observation for dc and ac connections. What happens in each if the capacitance of the capacitor is reduced ?
Show that in the free oscillations of an LC circuit, the sum of energies stored in the capacitor and the inductor is constant in time.
A point charge +Q is placed in the vicinity of a conducting surface. Draw the electric field lines between the surface and the charge.
Figure shows a point charge + Q, located at a distance R/2 from the centre of a spherical metal shell. Draw the electric field lines for the given system.
Nichrome and copper wires of same length and same radius are connected in series. Current I is passed through them. Which wire gets heated up more ? Justify your answer.
Does the charge given to a metallic sphere depend on whether it is hollow or solid?
How does the random motion of free electrons in a conductor get affected when a potential difference is applied across its ends ?
A point charge +Q is placed at point O as shown in the figure. Is the potential difference – positive, negative or zero ?