Question

The charge of electron is :

• A. \(1.6 \times 10^{-19} \text{ Coulomb}\)
• B. \(16 \times 10^{-19} \text{ Coulomb}\)
• C. \(0.16 \times 10^{-19} \text{ Coulomb}\)
• D. \(166 \times 10^{-19} \text{ Coulomb}\)

Hint:

The elementary charge (\(e\)) is a fundamental constant: Magnitude of charge on an electron = Magnitude of charge on a proton \(\approx 1.6 \times 10^{-19} \text{ C}\). Remember:
Electron's charge: \(-e = -1.6 \times 10^{-19} \text{ C}\)
Proton's charge: \(+e = +1.6 \times 10^{-19} \text{ C}\) The options provide magnitudes, so \(1.6 \times 10^{-19} \text{ C}\) is correct.

Answer 1

The Correct Option is A

Concept: The electron is a subatomic particle with a fundamental electric charge. This charge is known as the elementary charge, often denoted by \(e\). Step 1: Recalling the value of the elementary charge The magnitude of the charge on a single electron (and also on a proton) is a fundamental physical constant. The electron carries a negative charge, while a proton carries a positive charge of the same magnitude. The value of this elementary charge is approximately \(1.602 \times 10^{-19}\) Coulombs. For most introductory purposes, this is rounded to \(1.6 \times 10^{-19}\) Coulombs. Step 2: Understanding the options The question asks for "The charge of electron". Since an electron is negatively charged, its charge is actually \(-1.6 \times 10^{-19} \text{ C}\). However, multiple-choice questions often ask for the magnitude of the charge. All options are positive, implying the magnitude is being sought.
(1) \(1.6 \times 10^{-19} \text{ Coulomb}\): This matches the commonly accepted magnitude of the elementary charge.
(2) \(16 \times 10^{-19} \text{ Coulomb}\): This is \(1.6 \times 10^{-18} \text{ C}\), which is 10 times too large.
(3) \(0.16 \times 10^{-19} \text{ Coulomb}\): This is \(1.6 \times 10^{-20} \text{ C}\), which is 10 times too small.
(4) \(166 \times 10^{-19} \text{ Coulomb}\): This is \(1.66 \times 10^{-17} \text{ C}\), which is significantly different. Step 3: Identifying the correct value The magnitude of the charge of an electron is \(1.6 \times 10^{-19} \text{ Coulomb}\).