Class 12 Physics Quiz

Which one of the following is not a scalar quantity?

• Resistivity

• Voltage

• Electric field

• Power

Two charged particles P and Q, having the same charge but different masses and , start from rest and travel equal distances in a uniform electric field in time and respectively. Neglecting the effect of gravity, the ratio is :

• mP/mQ

• mQ/mP

• √(mP/mQ)

• √(mQ/mP)

A point P lies at a distance x from the mid point of an electric dipole on its axis. The electric potential at point P is proportional to

• 1/x^2

• 1/x

• 1/√x

• 1/x^3

Three small charged spheres X, Y and Z carrying charges + q, q and + q respectively are placed equidistant from each other, as shown in the figure. The spheres Y and Z are held in place. Initially X is also held in place, but is otherwise free to move. When X is released, the path followed by it will be:

• no net charge is enclosed by the surface

• electric potential varies from point to point inside the surface

• uniform electric field exists within the surface

• charge is present inside the surface

If the net electric flux through a closed surface is zero, then we can infer

• no current exists.

• only conduction current exists.

• both displacement current and conduction current exist.

• only displacement current exists.

A charge Q is kept at the centre of a circle of radius r. A test charge q0 is carried from a point X to the point Y on this circle such that arc XY subtends an angle of 60° at the centre of the circle. The amount of work done in this process will be

• (1/4πε0)(3√Qq0/r)

• (1/4πε0)(3√Qq0/2r)

• (1/4πε0)(Qq0/2r)

• C

The capacitance of a parallel plate capacitor having a medium of dielectric constant K = 4 in between the plates is C. If this medium is removed, then the capacitance of the capacitor becomes

• C

• C/4

• zero

• -2qEL

An electric dipole consisting of charges + q and - q separated by a distance L is in stable equilibrium in a uniform electric field. The electrostatic potential energy of the dipole is

• All three in parallel

• Two of them connected in series and the combination in parallel to the third.

• All three in series

• Two of them connected in parallel and the combination in series to the third.

The capacitors, each of 4μF are to be connected in such a way that the effective capacitance of the combination is 6μF. This can be achieved by connecting

• negative to positive terminal and positive to negative terminal

• positive to negative terminal and positive to negative terminal

• negative to positive terminal and negative to positive terminal

• positive to negative terminal and negative to positive terminal

In a dc circuit the direction of current inside the battery and outside the battery respectively are

• is along direction, but is along direction.

• is along direction, but is along direction.

• and both are along direction.

• and both are along direction.