Two infinitely long parallel plates of equal areas 6 cm2 are separated by a distance of 1 cm. While one of the plates has a charge of + 10 nC and the other has − 10 nC. The magnitude of the electric field between the plates, if F/m is
0.6 π kV/m
6 π kV/m
600 π kV/m
60 π V/m
The electric field strength in NC-1 that is required to just prevent a water drop carrying a charge 1.6 x10-19 C from falling under gravity is (g = 9.8 ms-2, mass of water drop = 0.0016 g)
9.8 × 10-16
9.8 × 1016
9.8 × 10-13
9.8 × 1013
A cylinder of radius r and length l is placed in a uniform electric field of intensity E acting parallel to the axis of the cylinder. The total flux over curved surface area is
Zero
Electric lines of force about a positive point charge are
radially outwards
circular clockwise
radially inwards
parallel straight lines
An electric dipole of moment µ of 400 µC m is placed in a transverse electric field (E) of 50 Vm-1 at an angle of 30° to E. Then, a torque of
10-2 Nm acts along the direction E
10-3 Nm acts along the direction µ
10-2 Nm acts normal to both E and µ
10-3 Nm acts along the direction E
C.
10-2 Nm acts normal to both E and µ
Given, P = 400 µC = 400 × 10-6 C
E = 50 Vm-1
θ = 30°
We know that, torque acting on an electric dipole,
where, P = dipole moment
= 400 × 10-6 × 50 × sin 30°
= 400 × 10-6 × 50 ×
= 200 × 50 × 10-6
= 10-2 N-m
This torque will act normal to both E and µ.
The velocity acquired by a charged particle of mass m and charge Q accelerated from rest by a potential of V is
mQV
An electron moving with a constant velocity v along X-axis enters a uniform electric field applied along Y-axis. Then, the electron moves
with uniform acceleration along Y-axis
without any acceleration along Y-axis
in a trajectory represented as y = ax2
in a trajectory represented as y = ax
A plane square sheet of charge of side 0.5 m has uniform surface charge density. An electron at 1 cm from the centre of the sheet experiences a force of 1.6 x 10-12 N directed away from the sheet. The total charge on the plane square sheet is (ε0 = 8.854 × 10-12 C2 m-2 N-1)
16.25 µC
− 22.15 µC
− 44.27 µC
144.27 µC
The time period of revolution of a charge q1 and of mass m moving in a circular path of radius r due to Coulomb force of attraction with another charge q2 at its centre is
When a comb rubbed with dry hair attracts pieces of paper. This is because the
comb polarizes the piece of paper
comb induces a net dipole moment opposite to the direction of field
electric field due to the comb is uniform
comb induces a net dipole moment perpendicular to the direction of field