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WAEC Physics 2024 Paper

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Question : 18

Total: 50

Two isolated charged spheres each of magnitude + 1.0 x 10

^{-6}

C are seperated by a distance of 2.0 x 10

^{-1}

m. Calculate the magnitude of the electrostatic force between them [K =

\frac{1}{4\pi E_o}

^{9}

^{2}

^{-2}

]

2.25 x 10 $^{-1}$ N
4.50 x 10 $^{-1}$ N
2.25 x 10 $^{1}$ N
4.50 x 10 $^{1}$ N

Solution:

Concept:

Use Coulomb's law for the electrostatic force between two point charges.

Explanation:

Coulomb's law is given by:

F = \frac{K q_1 q_2}{r^2}

Here,

q_1 = q_2 = 1.0 \times 10^{-6}\ \mathrm{C}

and

r = 2.0 \times 10^{-1}\ \mathrm{m} = 0.2\ \mathrm{m}

.

Substitute the values:

F = \frac{9 \times 10^{9} \times (1.0 \times 10^{-6})^2}{(0.2)^2}

F = \frac{9 \times 10^{9} \times 1.0 \times 10^{-12}}{0.04}

F = \frac{9 \times 10^{-3}}{0.04}

F = 2.25 \times 10^{-1}\ \mathrm{N}

Answer:

The magnitude of the electrostatic force is

2.25 \times 10^{-1}\ \mathrm{N}

.

So, the correct option is A.

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