Q. A nucleus ᵐₙX emits one α-particle and two β⁻-particles. The resulting nucleus is
A) ᵐ⁻⁴ₙ₋₂Y
B) ᵐ⁻⁶ₙ₋₄Z
C) ᵐ⁻⁶ₙZ
D) ᵐ⁻⁴ₙX
Explanation
[Solution from source] Alpha emission lowers mass number by 4 and atomic number by 2; each β⁻ raises atomic number by 1 with no mass change. Net: mass number m − 4, atomic number n − 2 + 2 = n, so the product is an isotope of X, ᵐ⁻⁴ₙX. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.