Physics

A positive charge Qis uniformly distributed along a circular ring of radius R. A small test charge q is placed at the centre of the ring as shown in figure. Then

(a) If q>0 and is displaced away from the centre in the plane of the ring it will be pushed back towards the centre

(b) If q<0 and is displaced away from the centre in the plane of the ring, it will never return to the centre an will continue moving till it hits the ring

(c) If q<0 , it will perform SHM for small displacement along the axis.

(d) Q at the centre of the ring is in an unstable equilibrium within the plalne of the ring for q>O

A positive charge Q is uniformly distributed along a circular ring of radius R. A small test charge q is placed at the centre of the ring figure. Then,

(a) If q > 0 and is displaced away from the centre in the plane of the ring, it will be pushed back towards the centre

(b) If q < 0 and is displaced away from the centre in the plane of the ring, it will never return to the centre and will continue moving till it hits the ring

(c) If q < 0, it will perform SHM for small displacement along the axis

(d) Q at the centre of the ring is in an unstable equilibrium within the plane of the ring for q > 0

Refer to the arrangement of arrangement of charges in figure and a gaussian surface of radius R with Q charge at the center. Then 

(a) Total flux through the surface of the sphere is $\frac{-Q}{\mathit{\epsilon }0}$ .

(b) Field on the surface of the sphere of the sphere is -Q/4 $\pi \epsilon$ ₀R².

(c) Flux through the surface of sphere due to 5Q is zero.

(d) Field on the surface of sphere due to -2Q is same everywhere

Consider a region inside which there are various types of charges but the total charge is zero. At points outside the region,
(a) The electric field is necessarily zero
(b) The electric field is due to the dipole moment of the charge distribution only
(c) The dominant electric field is ∝ 1/r³, for large r, where r is the distance from an origin in this regions r
(d) The work done to move a charged particle along a closed path, away from the region, will be zero

The electric field at a point is
(a) Always continuous
(b) Continuous if there is no charge at that point
(c) Discontinuous only if there is a negative charge at that point (d) discontinuous if there is a charge at that point

Multiple Choice Questions

(One or More than One Correct Answer Type)

If Ф_s E . dS = 0 over a surface, then

(a) The electric field inside the surface and on it is zero
(b) The electric field inside the surface is necessarily uniform
(c) The number of flux lines entering the surface must be equal tothe number of flux lines leaving it
(d) All charges must necessarily be outside the surface

A hemisphere is uniformly charged positively. The electric field at a point on a diameter away from the centre is directed .

(a) Perpendicular to the diameter

(b) Parallel to the diameter

(c) At an angle tilted towards the diameter

(d) At an angle tilted away from the diameter

A point charge +q is placed at a distance d from an isolated conducting plane. The field at a point P on the other side of the plane is

(a) Directed perpendicular to the plane and away from the plane
(b) Directed perpendicular to the plane but towards the plane
(c) Directed radially away from the point charge
(d) Directed radially towards the point charge

A glass full of hot milk is poured on the table. It begins to cool gradually. Which of the following is correct?

(a) The rate of cooling is constant till milk attains the temperature of the surrounding

(b) The temperature of milk falls off exponentially with time

(c) While cooling, there is a flow of heat from milk to the surrounding as well as from surrounding to the milk but the net flow of heat is from milk to the surrounding and that is why it cools

(d) All three phenomenon, conduction, convection and radiation are responsible for the loss of heat from milk to the surroundings

Figure shows electric field lines in which an electric dipole P is placed as shown. Which of the following statements is correct?

(a) The dipole will not experience any force
(b) The dipole will experience a force towards right
(c) The dipole will experience a force towards left
(d) The dipole will experience a force upwards