1. Which of the following nuclei undergo fission when struck by thermal neutrons?
a) U-235 and U-238
b) U-238 and Pu-239
c) U-235 and Pu-239
d) All three: U-235, U-238, Pu-239
Answer: c
2. What is the primary source of energy in the Sun?
a) Nuclear fusion
b) Nuclear fission
c) Chemical reactions
d) Mechanical energy
Answer: a
3. A nuclear reactor produces energy through:
a) Nuclear fusion
b) Spontaneous fission
c) Uncontrolled chain reaction
d) Controlled chain reaction
Answer: d
4. Which component in a nuclear reactor is used to slow down neutrons?
a) Heavy water
b) Coolant
c) Shielding
d) Control rods
Answer: a
5. Which of the following metals are used in making nuclear weapons?
a) Uranium and Radium
b) Uranium, Radium, and Plutonium
c) Radium and Plutonium
d) Uranium and Plutonium
Answer: d
6. If U-238 splits into two identical parts, the resulting nuclei will be:
a) Radioactive
b) Stable
c) Isotopes
d) Isobars
Answer: b
7. A nuclear chain reaction is self-sustaining because:
a) Each fission releases more neutrons
b) Neutrons are immediately absorbed
c) Graphite slows down fast neutrons
d) All of the above except neutron absorption
Answer: a
8. Which of the following statements about atomic bombs and nuclear reactors is true?
a) Only nuclear reactors use controlled fission
b) Hydrogen bombs use fission; atom bombs use fusion
c) Atom bombs use fusion; hydrogen bombs use fission
d) Both use controlled fission
Answer: a
9. The function of a moderator in a nuclear reactor is to:
a) Absorb excess neutrons
b) Control energy release
c) Cool the reactor
d) Slow down neutrons to thermal levels
Answer: d
10. Which statement is true about an intrinsic semiconductor at absolute zero?
a) It becomes a perfect conductor
b) It behaves like a metal
c) It becomes a superconductor
d) It behaves as an insulator
Answer: d
Fundamentals & Particle Physics
11. What determines the mass number of an atom?
a) Number of protons + electrons
b) Number of neutrons + electrons
c) Number of photons
d) Number of protons + neutrons
Answer: d
12. Which of the following particles can be added to the nucleus without altering its chemical properties?
a) Electrons
b) Protons
c) Neutrons
d) Alpha particles
Answer: c
13. Mesons are typically found in:
a) Laser beams
b) X-rays
c) Gamma rays
d) Cosmic rays
Answer: d
14. Match the particles with their approximate rest energies:
| Particle | Energy (MeV) |
|---|---|
| A. Electron | 3. 0.5 |
| B. Neutrino | 4. 0 |
| C. Neutron | 1. 940 |
| D. Pi-Meson | 2. 140 |
Answer: b (A–3, B–4, C–1, D–2)
15. Consider the de Broglie hypothesis:
- Particles exhibit wave-like properties
- Equal de Broglie wavelength implies equal momentum
Which statement(s) is/are correct?
a) Only 1
b) Only 2
c) Both 1 and 2
d) Neither
Answer: c
Electronics & Devices
16. When a p-type and an n-type semiconductor are joined, they form a:
a) Rectifier
b) Amplifier
c) Oscillator
d) Conductor
Answer: a
17. A semiconductor device allows current in one direction. If polarity is reversed, current drops to zero. It is a:
a) p-type semiconductor
b) n-type semiconductor
c) Intrinsic semiconductor
d) p-n junction
Answer: d
18. Which statement about cathode rays is incorrect?
a) They are negatively charged
b) Found in all gases
c) Electrons are their constituents
d) Hydrogen ions have no protons
Answer: d
Modern Applications & Concepts
19. What does the term “Dolby B or Dolby C” on audio systems indicate?
a) Frequency modulation system
b) Amplitude modulation system
c) Noise reduction circuitry
d) Compatibility with both AC and DC power
Answer: c
20. Remote sensing is defined as:
a) Gathering data from a distance without physical contact
b) Operating devices remotely
c) Wireless network access
d) Using satellites for communication
Answer: a
21. What does Bluetooth use for data transmission?
a) 2.4 GHz or 5 GHz frequency bands
b) Only for WWANs
c) Requires line-of-sight
d) All the above
Answer: a
22. What is the significance of the Higgs boson discovery?
a) Explains why particles have mass
b) Enables matter teleportation
c) Helps develop better nuclear fuels
d) All of the above
Answer: a