class 12 chapter 1,chapter 2 objective question based on potential and potential energy.

video  link for introduction of electrostatics

 https://youtu.be/w-IPgPOa7Uo

1. Four electric charges $+q,+q,-q$ and $-q$ are placed at the corners of a square of side $2L$ (see figure). The electric potential at point A, midway between the two charges $+q$ and $+q$, is     1.   2.3.4.zero 

 

2. In a region, the potential is represented by $V(x,y,z)=6x-8xy-8y+6yz$, where V is in volts and x, y, z are in meters. The electric force experienced by a charge of 2 coulomb situated at point (1, 1,1) is :

A .

65​N

B .

30N

C .

24N

D .

43N

3. The diagrams below show regions of equipotentials.

A positive charge is moved from A to b in each diagram.

A .

Maximum work is required to move q in figure (b)

B .

Maximum work is required to move q in figure(c)

C .

In all the cases the work done is the same.

D .

Minimum work is required to move q in figure(a)

4. If potential (in volts) in a region is expressed as V(x,y,z)=6xy−y+2yz

the electric field (in N/C)${\displaystyle N/C)}$ at point (1,1,0)${\displaystyle (1,1,0)}$ is

5. Three point charges +q,-2q and +q are placed at point (x=0,y=a,z=0), (x=0,y=0,z=0)and (x=a,y=0,z=0) respectively . The magnitude and direction of  the electric dipole moment vector of this charge assembly are 

a)  √2qa  along the line joining points( x=0,y=0,z=0) and( x=a,y=a,z=0)

b)√2aq along $+y$-direction

c)√2aq along $+x$-direction

d)  qa  along the line joining points( x=0,y=0,z=0) and( x=a,y=a,z=0)

6.Charges +q and −q are placed at points A and B respectively which are a distance 2L apart, C is the midpoint between A and B. The work done in moving a charge +Q along the semicircle CRD is: