Potential and Potential Energy Relation

Q.

Two charges $3\times {10}^{-8}$ and $2\times {10}^{-8}$ are located 15 cm apart.At what point on the line joining the two charges is the electric potential zero? Take potential at infinity to be zero.

Q. Two charges e and 3e are placed at a dis†an ce r. The dis†an ce of the point where the electric field intensity will be zero is

Q.

If the electric field intensity in a fair weather atmosphere is 100V/m, then the total charge on the earth surface is

Q. When is the electric field at point P zero?
1. +q------r------P------r------+q

2. 4q------2r------P----r----q

3. -4q-------r------q----r----P

4. -q------r------P------r------+q
here r is the distance between the charges.

Q. A charge $Q$ is placed in front of a conducting sphere at a distance $2r$ from center of sphere as shown in the figure. Potential at point $P$ on the surface of sphere due to induced charges is

1. 0
2. $\frac{kQ}{6r}$
3. $\frac{kQ}{2r}$
4. $\frac{kQ}{3r}$

Q.

Two tiny spheres carrying charges 1.5 μC and 2.5 μC are located 30 cm apart. Find the potential and electric field:

(a) at the mid-point of the line joining the two charges, and

(b) at a point 10 cm from this midpoint in a plane normal to the line and passing through the mid-point.

Q. An electron falls through a distance of 1.5cm in a uniform electric field of magnitude 20000 N/ C. Now the direction of the field is reversed keeping the magnitude unchanged and a proton falls through a same distance. Compute the time of fall in each case, neglecting gravity.

Q. Electric field intensity at point B due to a point charge Q kept at point A is 24 N/C and the electric potential at point B due to the same charge is 12J/C.Calculate the distance AB and the magnitude of charge Q.

Q. { Two particles }A and }B having charges of }}{+2\cdot00×10^{-6}C and of }-4.00×10^{-6}C respectively are }}{ held fixed at a separation of }20\cdot0cm. Locate the point(s) }}{ on the line }AB where (a) the electric field is zero (b) the }} electric potential is zero.

Q. A cavity is made inside a solid conducting sphere and a charge $q$ is placed inside the cavity at the centre. A charge $q_1$ is placed outside the sphere as shown in the figure. Point $A$ is inside the sphere and point $B$ is inside the cavity. Then

1. Electric field at point $A$ is zero.
2. Electric field at point $B$ is $\frac{1}{4\pi {ϵ}_0}\frac{q}{y^2}$
3. Potential at point $A$ is $\frac{1}{4\pi {ϵ}_0}[\frac{q_1}{a}+\frac{q}{R}]$
4. Potential at point $B$ is $\frac{1}{4\pi {ϵ}_0}[\frac{q_1}{a}+\frac{q}{R}+\frac{q}{y}-\frac{q}{r}]$

Q.

Work done in charging a capacitor is stored in it in the form of electrostatic energy, given by

1. 

2. 

3. 

4. 

Q. 57.A 5C charge experiences a force of 2000N when moved between two points separated by a distance 2 cm in uniform electric field. The potential difference between the two points is??

Q.

12 J of work has to be done against an existing electric field to take a charge of 0.01 from A to B. Hwo much is the potential difference $V_B-V_A$?

Q. Is the electric potential due to infinite line charge or infinite plane sheet of charge is finite or infinite

Q. In an unbiased p-n junction which of the following is correct? (1) p-side is at higher potential than n-side. (2) n-side is at higher potential than p-side. (3) Both p-side and n-side are at the same potential (4) Any of the above is possible depending upon the carrier density in the two sides.

Q. A hollow conducting sphere of inner radius $R$ and outer radius $2R$ is given charge $Q$ as shown in the figure, then the

1. Potential at $A$ and $B$ is same.
2. Potential at $O$ and $B$ are different.
3. Potential at $O$ and $C$ are different.
4. Potential at $A,B,C$ and $O$ is same.

Q. An unchanged conductor $\text{A}$ is brought near a positively charged conductor $\text{B}$, then

1. the charge on $\text{B}$ will increase but potential of $\text{B}$ will not change.
2. the charge on $\text{B}$ will not change but the potential of $\text{B}$ will decrease.
3. the charge on $\text{B}$ will decrease but potential of $\text{B}$ will not change.
4. the charge on $\text{B}$ will not change but the potential of $\text{B}$ will increase.

Q. Two charges q and -4q are kept on a straight line. At how many points on this line, the electric potential is zero a.Infinite b.3 c.2 d.1

Q.

Can the potential of a charged body be zero?

Q. A particle has a mass 400 times that of the electron and charge is double that of an electron. It is accelerated by 5V of potential difference. Initially the particle was at rest, then its final kinetic energy will be

1. 10 eV
2. 100 eV
3. 2000 ev
4. 5 eV

Q. The potential of the electric field produced by a point charge at any point (x, y, z) is given by; $V=3x^2-5$, where x, y, z are in metre and V is in volt. The intensity of the electric field at (-2, 1, 0) is:

1. +17 V/m
2. -17 V/m
3. +12 V/m
4. -12 V/m

Q. 102.The electric potential in some region is expressed by V=6x - 8xy2 - 8y + 6yz - 4z2 volt. The magnitude of force acting on a charge of 2C situated at the origin will be

Q.

The electrostatic potential energy of a system containing two charges 7 μC and - 2 μC separated by a distance of 18 cm is

1. + 1.7 J

2. -1.7 J

3. + 0.7 J

4. -0.7 J

Q. On moving a charge of 20 coulomb by 2 cm, 2J of work is done, then the potential difference between the points is:
[AIEEE - 2002]

1. 8 V
2. 2 V
3. 0.5 V
4. 0.1 V

Q. In which of the following forms the potential energy in the capacitor is stored $?$

1. Electrostatic
2. Magnetic
3. Gravitational
4. Elastic

Q. A cavity is made inside a solid conducting sphere and a charge $q$ is placed inside the cavity at the centre. A charge $q_1$ is placed outside the sphere, as shown in the figure. Point $A$ is inside the sphere and point $B$ is inside the cavity. Then

1. Electric field at point $A$ is zero.
2. Electric field at point $B$ is $\frac{1}{4\pi {ϵ}_o}\frac{q}{y^2}$.
3. Potential at point $A$ is $\frac{1}{4\pi {ϵ}_o}[\frac{q_1}{a}+\frac{q}{R}]$.
4. Potential at point $B$ is $\frac{1}{4\pi {ϵ}_o}[\frac{q_1}{a}+\frac{q}{R}+\frac{q}{y}-\frac{q}{r}]$

Q. If the anti-neutrino had a mass of $3eV/c^2$ (where c is the speed of light) instead of zero mass, what should be the range of the kinetic energy, K, of the electron?

1. $0\le K\le 0.8\times {10}^{6}eV$
2. $0\le K<0.8\times {10}^{6}eV$
3. $3.0eV\le K<0.8\times {10}^{6}eV$
4. $3.0eV\le K\le 0.8\times {10}^{6}eV$

Q. if work done by electrostatic force on a system of point charges is positive then the potential energy of system will ?? increase or decrease

Q.

Two point charges of 50 microC and 20 microC are separated by a distance of 2 m. Find the point on the line joining them at which electric field intensity is zero

Q. A hollow conducting sphere has inner radius $5\text{cm}$ and outer radius $8\text{cm}$, then find maximum possible potential of conductor, if breakdown electric field of air is $3\times {10}^6\text{V/m}$

1. $240\text{kV}$
2. $480\text{kV}$
3. $960\text{kV}$
4. $720\text{kV}$