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WorksheetsXII PHYSICS CH-1 ELECTROSTATICS
Total questions: 20
Worksheet time: 18mins
A glass rod rubbed with silk acquires a charge of +8 × 10−12C. The number of electrons it has gained or lost
5 × 10−7 (gained)
5 × 107 (lost)
2 × 10−8 (lost)
–8 × 10−12 (lost)
The electrostatic force between two point charges kept at a distance d apart, in a medium εr = 6, is 0.3 N. The force between them at the same separation in vacuum is
20 N
0.5 N
1.8 N
2 N
Electric field intensity is 400 V m−1 at a distance of 2 m from a point charge. It will be 100 V m−1 at a distance?
50 cm
4 cm
4 m
1.5 m
Two point charges +4q and +q are placed 30 cm apart. At what point on the line joining them the electric field is zero?
15 cm from the charge q
7.5 cm from the charge q
20 cm from the charge 4q
5 cm from the charge q
A dipole is placed in a uniform electric field with its axis parallel to the field. It experiences
only a net force
only a torque
both a net force and torque
neither a net force nor a torque
Which of the following quantities is scalar?
dipole moment
electric force
electric field
electric potential
The unit of permittivity is
C2 N−1 m−2
N m2 C−2
H m−1
N C−2 m−2
Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10-2 C and 5 x 10-2 C respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is
3 × 10-2 C
4 × 10-2 C
1 × 10-2 C
2 × 10-2 C
Two identical conducting balls having positive charges q1 and q2 are separated by a center to center distance r. If they are made to touch each other and then separated to the same distance, the force between them will be
less than before
same as before
more than before
zero
An electric dipole is placed at an alignment angle of 30o with an electric field of 2 × 105 N C-1. It experiences a torque equal to 8 N m. The charge on the dipole if the dipole length is 1 cm is
4 mC
8 mC
5 mC
7 mC
A hollow metal ball carrying an electric charge produces no electric field at points
outside the sphere
on its surface
inside the sphere
at a distance more than twice
Two similar spheres having +Q and -Q charges are kept at a certain distance. F force acts between the two. If at the middle of two spheres, another similar sphere having +Q charge is kept, then it experiences a force in magnitude and direction as
zero having no direction.
8F towards +Q charge.
8F towards -Q charge.
4F towards +Q charge.
The electric field intensity due to an infinite cylinder of radius R and having charge q per unit length at a distance rir r(r > R) from its axis is
directly proportional to r².
directly proportional to r3
inversely proportional to r.
inversely proportional to r²
Which of the following statement is correct? The electric field at a point is
always continuous.
continuous if there is a charge at that point
discontinuous only if there is a negative charge at that point.
discontinuous if there is a charge at that point
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
directed perpendicular to the plane and away from the plane.
directed perpendicular to the plane but towards the plane
directed radially away from the point charge
directed radially towards the point charge
The force per unit charge is known as
electric flux
electric field
electric potential
electric current
Which of the following statements is not true about Gauss’s law?
Gauss’s law is true for any closed surface.
The term q on the right side side of Gauss’s law includes the sum of all charges enclosed by the surface
Gauss’s law is not much useful in calculating electrostatic field when the system has some symmetry.
Gauss’s law is based on the inverse square dependence on distance contained in the coulomb’s law
Quantisation of charge implies
charge cannot be destroyed
charge exists on particles
there is a minimum permissible charge on a particle
charge, which is a fraction of a coulomb is not possible.
What happens when some charge is placed on a soap bubble?
Its radius decreases
Its radius increases
The bubble collapses
None of these
In annihilation process, in which an electron and a positron transform into two gamma rays, which property of electric charge is displayed?
Additivity of charge
Quantisation of charge
Conservation of charge
Attraction and repulsion
