How many electrons should be removed from a coin of mass 1.6 g so that it may float in an electric field of intensity ${10}^9$ N/C directed upwards?

1. $9.8\times {10}^7$

2. $9.8\times {10}^5$

3. $9.8\times {10}^3$

4. $9.8\times {10}^1$

ABC is an equilateral triangle. Charges +q are placed at each corner. The electric field intensity at the centroid of the triangle will be:

1. $\frac{1}{4{\mathrm{\pi \epsilon }}_0}\times \frac{\mathrm{q}}{{\mathrm{r}}^2}$

2. $\frac{1}{4{\mathrm{\pi \epsilon }}_0}\times \frac{3\mathrm{q}}{{\mathrm{r}}^2}$

3. $\frac{1}{4{\mathrm{\pi \epsilon }}_0}\times \frac{\mathrm{q}}{\mathrm{r}}$

4. Zero

A charge Q is placed at the centre of a square. If the electric field intensity due to the charges at the corners of the square is E₁ and the intensity at the midpoint of the side of the square is E₂, then the ratio $\frac{{\mathrm{E}}_1}{{\mathrm{E}}_2}$ will be:

1. $\frac{1}{2\sqrt{2}}$

2. $\sqrt{2}$

3. $\frac{1}{2}$

4. $2$

Point charges, each of magnitude Q, are placed at the three corners of a square as shown in the diagram. What is the direction of the resultant electric field at point A?

1. OC

2. OE

3. OD

4. OB

Two charges e and 3e are placed at a distance r. The distance of the point where the electric field intensity will be zero is:

1. $\frac{\mathrm{r}}{(1+\sqrt{3})}$ from 3e charge.

2. $\frac{\mathrm{r}}{(1+\sqrt{3})}$ from e charge.

3. $\frac{\mathrm{r}}{(1-\sqrt{3})}$ from 3e charge.

4. $\frac{\mathrm{r}}{1+\sqrt{{\displaystyle \frac{1}{3}}}}$ from e charge.

If the electric lines of force in a region are represented as shown in the figure, then one can conclude that the electric field is:

1. Non-uniform

2. Uniform

3. Both uniform and non-uniform

4. Zero everywhere

An uncharged sphere of metal is placed in a uniform electric field produced by two oppositely charged plates. The lines of force will appear as:

1. 

2. 

3. 

4. 

An electron released on the axis of a positively charged ring at a large distance from the centre will:

1. not move.

2. do oscillatory motion.

3. do SHM.

4. do non-periodic motion.

The figure shows electric lines of forces due to charges Q₁ and Q₂. Hence,

1. Q₁ and Q₂ both are negative.

2. Q₁ and Q₂ both are positive.

3. Q₁ > Q₂ 

4. Both (2) and (3)

The figure shows the electric lines of force. If E_x and E_y are the magnitudes of the electric field at points x and y respectively, then:

1. ${\mathrm{E}}_{\mathrm{x}}>{\mathrm{E}}_{\mathrm{y}}$

2. ${\mathrm{E}}_{\mathrm{x}}={\mathrm{E}}_{\mathrm{y}}$

3. ${\mathrm{E}}_{\mathrm{x}}<{\mathrm{E}}_{\mathrm{y}}$

4. Any of these