1. . Proton and electron have charges:
(A) Same
(B) Opposite
(C) No charge
(D) Double positive
2. . When α-emission takes place, the number of protons:
(A) Increases by two
(B) Decreases by two
(C) Increases by four
(D) Decreases by four
3. . When β-emission takes place, the atomic mass:
(A) Increases by two
(B) Decreases by two
(C) Increases by four
(D) Decreases by four
4. . Mass of a proton is:
(A) 1.67 × 10⁻²⁷ kg
(B) 1.67 × 10⁻³¹ kg
(C) 9.10 × 10⁻³¹ kg
(D) 1.67 × 10⁻¹⁷ kg
5. . Atomic number is equal to:
(A) Number of protons
(B) Number of neutrons
(C) Number of protons and neutrons
(D) All of these
6. . Elements showing radioactivity have atomic number:
(A) Z > 72
(B) Z > 83
(C) Z < 72
(D) Z < 83
7. . Mass number is equal to:
(A) Number of protons
(B) Number of neutrons
(C) Number of protons and neutrons
(D) All of these
8. . Gamma rays consist of a stream of:
(A) Electrons
(B) Protons
(C) Positrons
(D) Photons