Question: Enriched uranium means that, it contains___________________?

• 1. More than 0.71% of U-235
• 2. Only fertile material
• 3. Only fissile material
• 4. No impurities

Question: Which is a fertile nuclear fuel ?

• 1. U-233
• 2. U-235
• 3. Pu-239
• 4. Th-232

Question: Heavy water is used as a moderator in a _____________________?

• 1. Pressurised water reactor (PWR)
• 2. Boiling water reactor (BWR)
• 3. Candu reactor
• 4. Molten sodium cooled reactor

Question: Candu reactor is a ______________ nuclear reactor?

• 1. Natural uranium fuelled heavy water cooled & moderated
• 2. Highly enriched uranium (85% U-235) fuelled
• 3. Homogeneous
• 4. Fast breeder

Question: Which one is the radioactive isotope of hydrogen ?

• 1. Deuterium
• 2. Ortho-hydrogen
• 3. Tritium
• 4. None of these

Question: Pick out the wrong statement?

• 1. The disintegration rate of a radioactive substance cannot be increased by heating it
• 2. Electrons have negligible mass and unit negative change
• 3. Deuterium atom has one proton and two neutrons in its nucleus
• 4. Cadmium is capable of absorbing neutrons

Question: Pick out the correct statement?

• 1. Loss of electrons from neutral atoms produces negative ions
• 2. The radius of nucleus & atomic size are of the order of 10-12 cm & 10-8 cm respectively
• 3. Gain of electrons by neutral atoms form cations
• 4. Proton to neutron ratio in a stable nucleus is 2 : 1

Question: Pick out the correct statement?

• 1. Positron is the antiparticle of electron
• 2. In α-decay, the ratio of neutron to proton decreases
• 3. Ionising power of β-rays is higher than that of α-rays
• 4. Speed of α-rays is more than that of γ-rays

Question: Pick out the wrong statement?

• 1. The ratio of the density of the ‘nucleus’ to that of the ‘atom’ is 1012
• 2. α-particle is identical with a doubly charged helium ion
• 3. The mass of deuterium atom is half that of helium atom
• 4. Gamma rays are high energy electrons

Question: Pick out the wrong statement?

• 1. The nucleus of a hydrogen atom is identical with a proton
• 2. A, β-ray particle is identical with an electron
• 3. Mass of an electron is about 1/1800th of the lightest nucleus
• 4. Positron is heavier than a proton