1. Page from both: What is the new repulsion force between [tex]$B$[/tex] and [tex]$C$[/tex]? [tex]\[F = \frac{3}{2} F\][/tex]

2. Consider a system with two charges of magnitude [tex]$2 \times 10^{-7} \, C$[/tex] and [tex]$4.5 \times 10^{-7} \, C$[/tex] acted upon by a force of [tex]$0.1 \, N$[/tex]. What is the distance between the two charges? [tex]\[0.09 \, m\][/tex]

3. Consider two opposite charges with the same magnitude placed at a distance from each other such that the force between these two charges is [tex]$60\%$[/tex] of the original charge. If some charge is transferred to another, what is the value of the force in the new case? [tex]\[\frac{16}{25} F\][/tex]

4. A specific charge [tex]$Q$[/tex] is split into two components [tex]$q$[/tex] and [tex]$Q - q$[/tex]. What is the relation between [tex]$a$[/tex] and [tex]$q$[/tex] if the two portions are separated by distance [tex]$r$[/tex] and have the greatest Coulomb repulsion? [tex]\[\text{Ans: } q = \frac{Q}{2}\][/tex]



Answer :

Let's address the problems step-by-step. Specifically, we'll focus on question 5 which asks for the distance between two charges given their magnitudes and the force acting between them.

Firstly, the problem provides the following data:
1. Charge 1: [tex]\( Q_1 = 2 \times 10^{-7} \, \text{C} \)[/tex]
2. Charge 2: [tex]\( Q_2 = 4.5 \times 10^{-7} \, \text{C} \)[/tex]
3. Force between the charges: [tex]\( F = 0.1 \, \text{N} \)[/tex]
4. Coulomb’s constant: [tex]\( k = 8.99 \times 10^9 \, \text{N m}^2/\text{C}^2 \)[/tex]

The formula for the electrostatic force between two point charges is given by Coulomb's Law:
[tex]\[ F = k \frac{Q_1 Q_2}{r^2} \][/tex]

Here, we are tasked with finding the distance [tex]\( r \)[/tex] between the charges. Let's isolate [tex]\( r \)[/tex] in the equation.

1. Rearrange Coulomb's Law to solve for [tex]\( r^2 \)[/tex]:
[tex]\[ r^2 = k \frac{Q_1 Q_2}{F} \][/tex]

2. Substitute the values given into the equation:
[tex]\[ r^2 = \left(8.99 \times 10^9 \, \text{N m}^2/\text{C}^2\right) \times \left(\frac{2 \times 10^{-7} \, \text{C} \times 4.5 \times 10^{-7} \, \text{C}}{0.1 \, \text{N}}\right) \][/tex]

3. This evaluates to:
[tex]\[ r^2 = \left(8.99 \times 10^9 \right) \times \left(\frac{9 \times 10^{-14}}{0.1}\right) \][/tex]
[tex]\[ r^2 = \left(8.99 \times 10^9 \right) \times 9 \times 10^{-13} \][/tex]

4. Simplifying further, we get:
[tex]\[ r^2 = 8.091 \times 10^{-3} \, \text{m}^2 \][/tex]

5. Now, take the square root of both sides to find [tex]\( r \)[/tex]:
[tex]\[ r = \sqrt{8.091 \times 10^{-3}} \][/tex]

6. Therefore:
[tex]\[ r \approx 0.08995 \, \text{m} \][/tex]

Thus, the distance [tex]\( r \)[/tex] between the two charges is approximately [tex]\( 0.08995 \, \text{m} \)[/tex].

In summary, given the magnitudes of the charges and the force between them, the distance between the charges is approximately [tex]\( 0.08995 \, \text{m} \)[/tex], or about [tex]\( 0.09 \, \text{m} \)[/tex].