1. Radioactivity refers to the splitting of the:
a) Atom
b) Ion
c) Nucleus
d) Molecule
Answer: c
2. Match the following characteristics with their corresponding particles:
- A. Zero mass – 4. Photon
- B. Fractional charge – 3. Quark
- C. Fractional spin – 1. Positron
- D. Integral spin – 2. Neutrino
Correct code: a) 4 3 1 2
3. The SI unit of radioactivity is:
a) Radian
b) Becquerel
c) Steradian
d) Kelvin
Answer: b
4. Which element is essential in nuclear reactor construction?
a) Nickel
b) Cobalt
c) Zirconium
d) Tungsten
Answer: c
5. Who discovered the phenomenon of radioactivity?
a) Rutherford
b) Curie
c) Suri
d) Henri Becquerel
Answer: d
6. A substance with a half-life of 4 months will be 75% decayed in:
a) 3 months
b) 4 months
c) 8 months
d) 12 months
Answer: c
7. The final product formed after the radioactive decay of uranium is:
a) Polonium
b) Thorium
c) Radium
d) Lead
Answer: d
8. Cobalt-60 is widely used in radiation therapy because it emits:
a) Alpha rays
b) Beta rays
c) Gamma rays
d) X-rays
Answer: c
9. India’s first nuclear weapon test was conducted at:
a) Kanchipuram
b) Bangalore
c) Pokhran
d) Sriharikota
Answer: c
10. What differentiates a nuclear reactor from an atomic bomb?
a) No chain reaction occurs in reactors
b) Chain reaction is controlled in reactors
c) Chain reaction is uncontrolled in reactors
d) No chain reaction in bombs
Answer: b
11. Radioactivity is measured using a:
a) Calorimeter
b) Barometer
c) Polarimeter
d) Geiger-Muller counter
Answer: d
12. Which device detects gamma-emitting isotopes in drinking water?
a) Spectrophotometer
b) Microscope
c) Scintillation counter
d) Lead plate
Answer: c
13. Beta particles emitted during radioactive decay originate from:
a) Electron shells
b) Free electrons
c) Neutron decay in nucleus
d) Escaping photons
Answer: c
14. The heaviest naturally occurring element is:
a) Thorium
b) Uranium
c) Mercury
d) Polonium
Answer: b
15. Which of the following does not exhibit radioactivity?
a) Uranium
b) Thorium
c) Aluminium
d) Polonium
Answer: c
16. What was the fissionable material in the Nagasaki bomb (1945)?
a) Sodium
b) Potassium
c) Plutonium
d) Uranium
Answer: c
17. Which noble gas is radioactive?
a) Xenon (Xe)
b) Helium (He)
c) Neon (Ne)
d) Radon (Rn)
Answer: d
18. The correct decreasing order of penetration power is:
a) α > β > γ
b) γ > α > β
c) β > α > γ
d) γ > β > α
Answer: d
19. During which emission is there no change in mass or charge of the element?
a) Gamma emission
b) Oxidation
c) Alpha emission
d) Beta emission
Answer: a
20. Nuclear fission is triggered by the impact of:
a) Protons
b) Deuterons
c) Electrons
d) Neutrons
Answer: d
21. Which one of the following elements is radioactive?
a) Cobalt
b) Uranium
c) Argon
d) Chromium
Answer: b
22. What is a neuron?
a) A radioactive particle
b) Basic unit of nervous system
c) Energy unit
d) Antiparticle of neutron
Answer: b
23. Which of the following is radioactive?
a) Cesium
b) Platinum
c) Strontium
d) Thorium
Answer: d