What is the actual mass of a neutron?

Correct answer: d 1.675 × 10⁻²⁴ g

The neutron's mass is 1.675 × 10⁻²⁴ g, slightly more than the proton's. (The Bangla book's table prints 1.67 × 10⁻²⁴ g.)

Why the other options are wrong

• a 1.60 × 10⁻¹⁹ g: 1.60 × 10⁻¹⁹ is the size of the charge in coulombs, not a mass; the neutron's mass is 1.675 × 10⁻²⁴ g.
• b 9.110 × 10⁻²⁸ g: This is the electron's mass; the neutron's is 1.675 × 10⁻²⁴ g.
• c 1.673 × 10⁻²⁴ g: This is the proton's mass; the neutron is slightly heavier, 1.675 × 10⁻²⁴ g.