The capacitance of earth, viewed as a spherical conductor of radius 6408 km is:
(a) 1420 μF
(b) 712 μF
(c) 680 μF
(d) 540 μF
(a) 1420 μF
(b) 712 μF
(c) 680 μF
(d) 540 μF
(b) 712 μF
The electric potential due to point charge 3 nC at distance of 9 cm is
(a) 270 v
(b) 3 v
(c) 300 v
(d) 30 v
The capacitance of a capacitor will decrease if we introduce a slab of:
(a) copper
(b) aluminium
(c) zinc
(d) None of these
Choose the SI unit of electric potential energy :
(a) Joule
(b) Coulomb
(c) Newton per coulomb
(d) Erg
Minimum number of capacitor of 2μF each required to obtain a capacitance of 5μF will be:
(a) 4
(b) 3
(c) 5
(d) 6
The electrostatic potential energy between proton and electron separated by a distance of 1 Å is
(a) 13.6eV
(b) 27.2eV
(c) -14.4eV
(d) 1.44eV
A wire of resistance 0.5 Ωm⁻¹ is bent into a circle of radius 1m. The same wire is connected across a diameter AB as shown in the fig. The equivalent resistance is
(a) Π ohm
(b) Π (Π + 2) ohm
(c) Π/( Π + 4) ohm
(d) (Π + 1) ohm
The ratio of magnetic length to geometric length of a magnet is
a) 0.084
b) 8.4
c) 80.4
d) 0.84
For sustained interference, we need two sources which emit radiations:
(a) of the same intensity
(b) of the same amplitude
(c) having a constant phase difference
(d) None of these
The parameter of light wave which remain same after refraction
(A) speed
(B) frequency
(C) wavelength
(D) none of these
Law stating that, force is directly proportional to product of charges and inversely proportional to square of separation between them, is
(A) Newton’s law
(B) Coulomb’s law
(C) Gauss’s law
(D) Ohm’s law
In an interference pattern produced by two identical slits, the intensity at the site of maxima is I. When one of the slit is closed, the intensity at the same spot is I0. What is the relation between I and \(I_0\)
(a) I = 2 \(I_0\)
(b) I = 4 \(I_0\)
(c) I = 16 \(I_0\)
(d) I = \(I_0\)
A Galvanometer is said to be sensitive, when-
a) Small deflection for a small current
b) Small deflection for a large current
c) large deflection for a small current
d) large deflection for a large current .