Twenty-seven drops of mercury are charged simultaneously to the same potential of 10 volts. What will be potential if all the charged drops are made to combine to form one large drop ?
(a) 180 V
(b) 90 V
(c) 120 V
(d) 45 V
(a) 180 V
(b) 90 V
(c) 120 V
(d) 45 V
(b) 90 V
Two capacitors of capacitance 6 µF and 4 µF are put in series across a 120 V battery. What is the potential difference across the 4 µF capacitor?
(a) 72 V
(b) 60 V
(c) 48 V
(d) zero
If 100 J of work has to be done in moving an electric charge of 4 C from a place, where potential is -10 volt to another place where potential is V volt,find the value of V.
(a) 5 V
(b) 10 V
(c) 25 V
(d) 15 V
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
An electric charge of 425 f μC is removed from a fully charged capacitor of capacitance 8.5μF. Its potential will be lowered by:
(a) 75 V
(b) 100 V
(c) 85 V
(d) 50 V
The amount of work required to increase the distance between -6µC and 4µC from 6 cm to 18 cm will be :
(a) 1.8 J
(b) 2.4 J
(c) 1.8 µJ
(d) 2.4 µJ
Three capacitors 3 μF, 6 μF and 6 μF are connected in series to a source of 120 volt. The potential difference across the 3 μF capacitor will be
(a) 40 volt
(b) 30 volt
(c) 40 volt
(d) 60 volt
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
Huygens theory could not explain
a. Reflection of light
b. Photoelectric effect
c. Interference of light
d. Diffraction of light
What happens if one of the slits, say S1 in Young’s double, slit experiment-is covered with a glass plate which absorbs half the intensity of light from it?
(a) The bright fringes become less-bright and the dark fringes have a finite light intensity.
(b) The bright fringes become brighter and the dark fringes become darker.
(c) The fringe width decreases.
(d) No fringes will be observed.
A negatively charged oil drop is prevented from falling under gravity by applying a vertical electric field 100 V/m. If the mass of the drop is 1.6 x \(10^{-3}\)g, the number of electrons carried by the drop is (g=10m/\(s^2\))
(A)\(10^{18}\)
(B)\(10^{15}\)
(C)\(10^{12}\)
(D)\(10^9\)
Unit of magnetic dipole moment is
a) ampere meter
b) ampere/meter⁻¹
c) ampere metre²
d) ampere/metre²
A plane wave passes through a convex lens. The geometrical shape of the wavefront that emerges is
(a) plane
(b) diverging spherical
(c) converging spherical
(d) None of these
Minimum number of capacitor of 2μF each required to obtain a capacitance of 5μF will be:
(a) 4
(b) 3
(c) 5
(d) 6
In a double slit interference pattern, the first maxima for infrared light would be
a. at the same place as the first maxima for green light
b. closer to the centre than the first maxima for green light
c. farther from the centre than the first maxima for green light
d. infrared light does not produce an interference pattern