Electrostatic Potential and Capacitance

abcd

• dfgdx

• sfd

• sdf

• sdfsdf

How much work must we do on an electron to move it from point A, which is at a potential of +50V, to point B, which is at a potential of -50 V, along the semicircular path shown in the figure? Assume the system is isolated from outside forces. (e = 1.60 × 10^-19 C)

• 1.60 × 10^-17 J
• -1.6 J
• 1.6 J
• -1.60 × 10^-17 J

A positive charge  $Q$  is placed very close to the positive plate of a parallel plate capacitor that produces an electric field  $E$ . Once released, the positive charge reaches the negative plate a distance  $d$  away with a kinetic energy of

•  $Ed$  

•  $QEd$  

•  $2Ed$  

•  $2QEd$  

Inserting a dielectric material between two charged parallel conducting plates, originally separated by air and disconnected from a battery, will produce what effect on the capacitor?

• increase charge

• increase voltage

• increase capacitance

• decrease capacitance

As a proton moves in the direction the electric field lines...

• it is moving from low potential to high potential and gaining electric potential energy.
• it is moving from low potential to high potential and losing electric potential energy.
• it is moving from high potential to low potential and gaining electric potential energy.
• it is moving from high potential to low potential and losing electric potential energy.

Electric potential at a point due to a dipole is

• $\frac{1}{4πε_o}\ \frac{p⃗.r⃗}{r^3}$

• $\frac{1}{4πε_o}\ \frac{p⃗.r⃗}{r^2}$

• $\frac{1}{4πε_o}\ \frac{p⃗.r⃗}{r}$

• $\frac{1}{4πε_o}\ p⃗.r⃗$

The electric field inside a spherical shell of uniform surface charge density is-

• zero.

• constant, less than zero.

• directly proportional to the distance from the centre.

• none of the these

If three 4.0 µF capacitors are connected in parallel, what is the combined capacitance?

• 12 µF

• 0.75 µF

• 8.0 µF

• 0.46 µF

Electric potential at a point due to a dipole is

The relation between electric field and electric potential is

• $E=dV.dr$

• $V=dE.dr$

• $V=-\frac{dE}{dr}$

• $E=-\frac{dV}{dr}$