A capacitor of capacity C has reactance X. If capacitance and frequency become double then reactance will be
(a) 4X
(b) X/2
(c) X/4
(d) 2X
(a) 4X
(b) X/2
(c) X/4
(d) 2X
(c) X/4
A 40 mF capacitor is connected to a 200 V, 50 Hz ac supply. The r.m.s value of the current in the circuit is, nearly
(a) 1.7 A
(b) 2.05 A
(c) 2.5 A
(d) 25.1 A
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
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.
Huygens theory could not explain
a. Reflection of light
b. Photoelectric effect
c. Interference of light
d. Diffraction of light
A dielectric induces....... in an external electric field which decreases the net electric field.
(a) current
(b) dipole moment
(c) magnetic field
(d) polarisation
What happens to the interference pattern, the two slits S1 and S2 in Young’s double slit experiment are illuminated by two independent but identical sources?
a. The intensity of the bright fringes doubled
b. The intensity of the bright fringes becomes four times
c. Two sets of interference fringes overlap
d. No interference pattern is observed.
In interference pattern, the energy is
A) created at maximum
(B) destroyed at minimum
(C) conserves but re-disturbed
(D) none of the above
Which of the following phenomenon is not explained by Huygen’s wave theory?
(a) Diffraction
(b) Polarisation
(c) Photoelectric effect
(d) Interference
Wavefront is the locus of all points, where the particles of the medium vibrate with the same
(a) phase.
(b) amplitude.
(c) frequency.
(d) period.
Which of the following statements indicates that light waves are transverse?
(a) Light waves can be polarised
(b) Light waves can show interference
(c) Light waves undergo diffraction
(d) They travel in the vacuum