Properties of Field Lines

Q.

At which point is the electric field stronger?

Q. Identify the correct statement regarding an equipotential surface:

1. An equipotential surface and electric line of force intersect at an angle of ${90}^{\circ }$.
2. An equipotential surface and electric line of force intersect at an angle of ${60}^{\circ }$.
3. An equipotential surface and electric line of force intersect at an angle of ${45}^{\circ }$.
4. An equipotential surface and electric line of force never intersect each other.

Q. Two point charges placed at a distance $r$ in air exert a force $F$ on each other. What will be the distance at which they will experience force $4F$, when placed in a medium of dielectric constant $16$?

1. $r$
2. $\frac{r}{4}$
3. $\frac{r}{8}$
4. $2r$

Q. Which of the following graph of electrostatic force between two positive charges $\left(F_e\right)$ vs $r^2$, is a correct representation?
($r$ is the distance between two charges)

1. 
2. 
3. 
4. 

Q. A charge $Q$ is placed at a distance $L$ from the charge $-2q$ as shown in figure.

The system of three charges will be in equilibrium, if $Q$ is equal to

1. $-4q$
2. $+4q$
3. $-8q$
4. $+8q$

Q. For the given spherical Gaussian surface around and centred at infinite positive line charge, the angle between electric field $\overrightarrow{E}$ and area vector $\overrightarrow{A}$, at all the point on the surface is

1. ${90}^{\circ }$
2. equal but not $0^{\circ }$ or ${90}^{\circ }$
3. not equal
4. $0^{\circ }$

Q. Four point charges $-Q,-q,2q$ and $2Q$ are placed, one at each corner of the square. The relation between $Q$ and $q$ for which the potential at the centre of the square is zero is
[NEET-2012 (Pre)]

1. $Q=q$
2. $Q=-\frac{1}{q}$
3. $Q=-q$
4. $Q=\frac{1}{q}$

Q.

Where is the electric field the largest?

Q. A charged particle of specific charge $\alpha$ enters in a magnetic field $\overrightarrow{B}=\frac{B_0}{\sqrt{2}}(\hat{j}+\hat{k})$ with a velocity $\overrightarrow{v}=v_0\hat{i}$. Then (specific charge = charge per unit mass)

Q. A cavity having a point charge $q$ is made in a neutral conductor as shown in the figure. The net electric field at point $\text{P}$ is
[$K=\frac{1}{4\pi {ϵ}_0}$]

1. $\frac{Kq}{R^2}$
2. Zero
3. $\frac{Kq}{x^2}$
4. $\frac{Kq}{r^2}$

Q. The figure given below shows four orientations of an electric dipole in an external electric field.

1. Workdone to rotate dipole from $\left(1\right)$ to $\left(2\right)$ is same as workdone to rotate dipole from $\left(1\right)$ and $\left(4\right)$.
2. If the dipole rotates from orientation $\left(1\right)$ to $\left(2\right)$, then the workdone on the dipole by field is positive.
3. Potential energy of dipole is greater for orientations $\left(1\right)$ and $\left(3\right)$ than $\left(2\right)$ and $\left(4\right)$.
4. If the dipole rotates from orientation $\left(1\right)$ to $\left(2\right)$, then the workdone on the dipole by field is negative.

Q.

[CPMT 1986, 88]

1. 

2. 

3. 

4. 

Q.

If $E_A,E_B,E_{C}and{E}_D$ represent the magnitudes of electric fields at A, B, C and D. Which of the options are correct?

1. $E_A>E_B>E_D>E_C$

2. $E_A<E_B<E_D<E_C$

3. $E_A>E_B>E_C>E_D$

4. $E_A<E_B<E_C<E_D$

Q. The plates of a parallel plate capacitor have an area of $90c{m}^2$ each and are separated by $2mm$. The capacitor is charged by connecting it to a $400V$ supply. Then the energy density of the energy stored $\left(inJ{m}^{-3}\right)$ in the capacitor is (Take ${ϵ}_0=8.8\times {10}^{-12}F{m}^{-1}$)

1. $0.113$
2. $0.117$
3. $0.152$
4. $\text{None of these}$