1. Inside a hollow charged spherical conductor, the
potential
a) Is constant
b) Varies directly as the distance from the centre
c) Varies inversely as the distance from the
centre
d) Varies inversely as the square of the distance
from the centre
Explanation: Inside the hollow sphere, at any point the potential is constant.
2. Two small spheres each carrying a charge q are
placed r metre apart. If one of the spheres is
taken around the other one in a circular path of
radius r , the work done will be equal to
a) Force between them \[\times r\]
b) Force between them \[\times 2 \pi r\]
c) Force between them \[/ 2 \pi r\]
d) zero
Explanation: The force is perpendicular to the displacement.
3.The electric charge in uniform motion produces
a) An electric field only
b) A magnetic field only
c) Both electric and magnetic field
d) Neither electric nor magnetic field
Explanation: A movable charge produces electric field and magnetic field both.
4. Two charged spheres of radii 10 cm and 15 cm are
connected by a thin wire. No current will flow, if
they have
a) The same charge on each
b) The same potential
c) The same energy
d) The same field on their surfaces
Explanation: Because current flows from higher potential to lower potential.
5. The electric field inside a spherical shell of
uniform surface charge density is
a) Zero
b) Constant, less than zero
c) Directly proportional to the distance from the
centre
d) None of the above
Explanation: All charge resides on the outer surface so that according to Gauss law, electric field inside a shell is zero.
6. The electric potential V at any point O (x, y, z all
in metres) in space is given by volt \[V=4 x^{2 }volt\] . The
electric field at the point \[\left(1m,0,2m\right)\] in volt / metre is
a) 8 along negative X - axis
b) 8 along positive X - axis
c) 16 along negative X - axis
d) 16 along positive Z - axis
Explanation:
7.A hollow metal sphere of radius 5 cm is charged
so that the potential on its surface is 10 V. The
potential at the centre of the sphere is
a) 0 V
b) 10 V
c) Same as at point 5 cm away from the surface
d) Same as at point 25 cm away from the surface
Explanation: Since potential inside the hollow sphere is same as that on the surface.
8. If a unit positive charge is taken from one point to
another over an equipotential surface, then
a) Work is done on the charge
b) Work is done by the charge
c) Work done is constant
d) No work is done
Explanation: On the equipotential surface, electric field is normal to the charged surface (where potential exists) so that no work will be done.
9.Electric lines of force about negative point charge
are
a) Circular, anticlockwise
b) Circular, clockwise
c) Radial, inward
d) Radial, outward
Explanation:
10. Charges of \[+\frac{10}{3}\times 10^{-9} C\] are placed at each of the
four corners of a square of side 8 cm. The
potential at the intersection of the diagonals is
a) \[150\sqrt{2}\] volt
b) \[1500\sqrt{2}\] volt
c) \[900\sqrt{2}\] volt
d) 900 volt
Explanation:
