Question

The study of radioactive decay results in the emission of particles, leading to four observations: (A) No change in atomic and mass number, (B) Atomic number decreases by 1, (C) Study of radioactive decay of unstable nuclei resulting in emission of a
particle leads us to four different observations listed below:
(A) Nochange in atomic number and mass number.
(B) Nochange in mass number but the atomic number decreases by 1.
(C) Nochange in mass number but the atomic number increases by 1.
(D) Atomic number decreases by 2 and the mass number decreases by 4.
Arrange the particles emitted in the above four cases in correct sequence:

• A. Alpha particle, positron, electron, photon
• B. Alpha particle, electron, positron, photon
• C. Photon, positron, electron, alpha particle
• D. Alpha particle, positron, photon, electron

Answer 1

The Correct Option is C

The problem requires identifying the particle emissions associated with changes in atomic and mass numbers during radioactive decay. Let's examine each observation and match it with the correct particle emission: 

(A) No change in atomic number or mass number: This is characteristic of gamma emission, which involves the emission of photons since photons have no mass or charge.

(B) No change in mass number but the atomic number decreases by 1: This indicates positron emission, which involves a proton converting into a neutron and emitting a positron.

(C) No change in mass number but the atomic number increases by 1: This corresponds to beta decay where a neutron turns into a proton, emitting an electron (beta particle).

(D) Atomic number decreases by 2, and the mass number decreases by 4: This occurs during alpha decay, where an alpha particle (helium nucleus) is emitted.

Based on the analysis, the correct order of particles is: Photon, positron, electron, alpha particle.

Answer 2

Given Observations:

Observation	Atomic Number Change	Mass Number Change	Particle Emitted
A	No change	No change	Photon (γ)
B	Decreases by 1	No change	Positron (β⁺) or Electron Capture
C	Increases by 1	No change	Electron (β⁻)
D	Decreases by 2	Decreases by 4	Alpha particle (α)

Correct Sequence:

From the table, the particles correspond to:

γ (A), β⁺ (B), β⁻ (C), α (D)

Answer: The correct sequence is \(\boxed{\text{photon, positron, electron, alpha particle}}\) (Option 3)