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
(a) we close the switch
(b) open the switch
(c) increasing the resistance
(d) decreasing the resistance
(b) open the switch
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
In an A.C. circuit, Irms and I₀ are related as
(a) Irms = p I₀
(b) Irms = 2 I₀
(c) Irms = I₀/p
(d) Irms =I₀ / 2
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.
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.
In electric arc furnace Cu or Iron is melted due to variation of
(a) current
(b) magnetic field
(c) voltage
(d) electric field
Obtain the expression for the energy density of magnitude field B produced in the inductor.
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.
An alternating e.m.f. of angular frequency ω is applied across an inductance. The instantaneous power developed across it has an angular frequency
(a) ω/4
(b) ω/2
(c) ω
(d) 2 ω
In Young’s double slit experiment the distance between the slit and the screen is doubled and the separation between the slit is reduced to half. The fringe width:
(a) is doubled
(b) become four time
(c) is halved
(d) remain unchanged
A Daniel cell is balanced on 125 cm length of a potentiometer wire. When the cell is short circuited with a 2 Ω resistance, the balancing length obtained is 100 cm. Internal resistance of the cell will be
(a) 1.5 Ω
(b) 0.5 Ω
(c) 1.25 Ω
(d) 4/5 Ω
A capacitor is connected across a battery and the plate separation of capacitor is increased without removing the battery, then:
(a) capacitance will increase
(b) charge stored will increase
(c) energy stored will decrease
(d) potential difference will increase
The colours on the soap bubble is due to
(a) Interference
(b) Diffraction
(c) Polarisation
(d) Reflection
In interference pattern, the energy is
A) created at maximum
(B) destroyed at minimum
(C) conserves but re-disturbed
(D) none of the above
If a charge q is placed at the center of the line joining two equal charges Q such that the system is in equilibrium, then the value of q is
(A)Q/2
(B)-Q/2
(C)Q/4
(D)-Q/4