Two identical charges situated 20cm apart in vacuum repel each other with a force of 1.0N.Calculate the value…

Analyze the question: Two identical charges, 0.20 m apart, repel with a force of 1.0 N. We need the value of each charge. The constant is 1/(4πε₀) = 9 × 10⁹ N m² C⁻². The question prints "14πε₀", which is a typo for 4πε₀.

Concept: Coulomb's law gives F = kQ²/r², so Q = r√(F/k).

Solution:

• r = 20 cm = 0.20 m
• Q² = F r² / k = (1.0 × 0.04) / (9 × 10⁹) = 4.44 × 10⁻¹² C²
• Q = √(4.44 × 10⁻¹²) ≈ 2.1 × 10⁻⁶ C

So Q ≈ 2.1 μC.

Checking the options: The result is 2.1 μC, so option A is probably meant to read 2.1 μC. The "21 μC" in the question is likely a typo for 2.1 μC. Taken literally, 21 μC would give a force of about 99 N, which is wrong. The other options (3.6, 4.0, 4.4 μC) do not match the calculation. Option A, read as 2.

Answer: A (2.1 μC, printed as 21 μC)

Tip: For Coulomb's law problems, convert cm to m first, then take the square root at the end. If the answer you get is not among the options, check for a decimal-point or typo issue in the options before assuming your working is wrong.