One particle has a charge of [tex]$2.15 \times 10^{-9}$[/tex] C, while another particle has a charge of [tex]$3.22 \times 10^{-9}$[/tex] C. If the two particles are separated by 0.015 m, what is the electromagnetic force between them? The equation for Coulomb's law is [tex]$F_e=\frac{k q_1 q_2}{r^2}$[/tex], and the constant [tex][tex]$k$[/tex][/tex] equals [tex]$9.00 \times 10^9 \, \text{N} \cdot \text{m}^2 / \text{C}^2$[/tex].

A. [tex]$4.15 \times 10^{-6} \, \text{N}$[/tex]

B. [tex][tex]$2.77 \times 10^{-4} \, \text{N}$[/tex][/tex]

C. [tex]$6.22 \times 10^{-4} \, \text{N}$[/tex]

D. [tex]$4.31 \times 10^{-7} \, \text{N}$[/tex]



Answer :

To determine the electromagnetic force between two charged particles, we will use Coulomb's law, which is given by the equation:

[tex]\[ F_e = \frac{k \cdot q_1 \cdot q_2}{r^2} \][/tex]

Where:
- [tex]\( F_e \)[/tex] is the electromagnetic force.
- [tex]\( k \)[/tex] is Coulomb's constant ([tex]\( 9.00 \times 10^9 \, N \cdot m^2 / C^2 \)[/tex]).
- [tex]\( q_1 \)[/tex] and [tex]\( q_2 \)[/tex] are the charges of the particles.
- [tex]\( r \)[/tex] is the distance between the two charges.

Given data:
- [tex]\( q_1 = 2.15 \times 10^{-9} \, C \)[/tex]
- [tex]\( q_2 = 3.22 \times 10^{-9} \, C \)[/tex]
- [tex]\( r = 0.015 \, m \)[/tex]

Now, let's substitute these values into the Coulomb's law equation and solve for [tex]\( F_e \)[/tex].

[tex]\[ F_e = \frac{(9.00 \times 10^9 \, N \cdot m^2 / C^2) \cdot (2.15 \times 10^{-9} \, C) \cdot (3.22 \times 10^{-9} \, C)}{(0.015 \, m)^2} \][/tex]

First, calculate [tex]\( r^2 \)[/tex]:

[tex]\[ r^2 = (0.015 \, m)^2 = 0.000225 \, m^2 \][/tex]

Next, calculate the numerator:

[tex]\[ (9.00 \times 10^9) \cdot (2.15 \times 10^{-9}) \cdot (3.22 \times 10^{-9}) = 6.2145 \times 10^{-8} \, N \cdot m^2 / C^2 \][/tex]

Now, divide the numerator by [tex]\( r^2 \)[/tex]:

[tex]\[ F_e = \frac{6.2145 \times 10^{-8}}{0.000225} \][/tex]

Finally, compute the force:

[tex]\[ F_e = 0.0002769200000000001 \, N \][/tex]

Rounding to two significant figures, as given in the options:

[tex]\[ F_e \approx 2.77 \times 10^{-4} \, N \][/tex]

Therefore, the electromagnetic force between the two particles is closest to the choice:

[tex]\[ \boxed{2.77 \times 10^{-4} \, N} \][/tex]

The correct answer is:
B. [tex]\( 2.77 \times 10^{-4} \, N \)[/tex]