ELECTRIC CHARGES AND FIELDS

1. Two charges 3x $10^{-5}$  C and 5x $10^4$   C are placed at a distance 10 cm from each other. Find the value of electrostatic force acting between them.

•  $13.5\times10^{11}$ N 

•  $40\ \times\ 10^{11^{ }}$  

•  $180\times10^9$  

•  $13.5\times10^{10}$  

What is the S. I. unit of electric flux?

• $\frac{N}{C}m^2$

• $\frac{N}{m^2}C^2$

• $N\ m^2$

• $\frac{N}{m^2}C^{ }$

A glass rod acquires charge by rubbing it with silk cloth. The charge on glass rod is due to :

• Conduction

• Induction

• Radiation

• Friction

What will be the value of electric field at the centre of the electric dipole : -

• Zero

• Equal to the electric field due to one charge at centre

• Twice the electric field due to one charge at centre

• half the value of electric field due to one charge at centre

Charge Q is kept in a sphere of 5 cm first than it is kept in a cube of side 5 cm. the outgoing flux will be-

• More in case of sphere

• More in case of cube

• Same in both cases

• None of the above

A pith ball has an electric charge +2q, 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 charged to -3q, the force on the pith ball is ---.

• 6F

• 2F

• 3F

• F

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

At which point is the electric field the weakest?

• A because it is the furthest away
• A because the field lines are further apart
• C because the field lines are further apart
• C  because it is the furthest away

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

• +,+
• +,-
• -,+
• -,-

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.