12th CBSE Chapter1

In comparison With the electrostatic force between two electrons, the electrostatic force between two protons is:

• greater

• smaller

• zero

• same.

Answer explanation

An electric dipole of moment p is placed in the position of stable equilibrium in a uniform electric field E . The couple required to rotate it through an angle 6 the initial position is:

• -PE cos θ

• PE tan θ

• PE cos θ

• PE sin θ

Force per unit charge is known as

• 1. Electric field

• 1. Current

• 1. Electric flux

• 1. Electric potential

Answer explanation

The space or region around an electric charge in which other charged particles can feel the electrostatic force is described as an electric field by that electric charge. The electric field is indicated by E, and the SI unit for it is N/C. The electric field is defined as the force per unit charge (E = F/q).

Charge given to a spherical conductor is uniformly distributed in its entire volume.

• True

• False

Electric field lines contracts lengthwise, It shows

• repulsion between same charges

• Attraction between apposite charges

• No relation between force & contraction.

• Electric field lines does not moves on straight path.

The diagram above shows a point, P, located midway between two oppositely charged parallel plates.

If an electron is introduced at point P, the electron will

• accelerate toward the negatively charged plate

• travel at constant speed toward the negatively charged plate

• travel at constant speed toward the positively charged plate

• accelerate toward the positively charged plate

Consider the electric field lines shown in the diagram below. From the diagram, it is apparent that object A is ____ and object B is ____.

• +,+
• +,-
• -,+
• -,-

A pith ball has an electric charge +q, and it feels a force F when placed a distance d from a second pith ball with an electric charge +q. When the second pith ball is moved to a distance 2d, the force on the pith ball is ---.

• 2F

• 1/2 F

• F

• 1/4 F

A hollow metal ball-carrying an electric charge produces no electric field at points:

1. 
   

• 1. Outside the sphere

• 1. On its surface

• 1. Inside the sphere

• 1. Only at the center

Answer explanation

The electric field within the hollow sphere is zero. They cancel each other out since E is a vector quantity. There is no electric field in the middle. The external field is canceled by the inside field. The electrical charge is always spread evenly throughout the uniformly formed wire.

The quantization of charge indicates that

• 1. Charge, which is a fraction of charge on an electron, is not possible

• 1. A charge cannot be destroyed

• 1. Charge exists on particles

• 1. There exists a minimum permissible charge on a particle

Answer explanation

The quantization of charge means that when we say something has some charge, we mean by that that how many times the charge of electrons it has. Because the whole charge is associated with an electron.