Nuclei quiz

The radius of a nucleus is proportional to:

Nuclear density:

The energy equivalent of 1 u is about:

The binding energy per nucleon is maximum for nuclei near:

Nuclear force is:

Isotopes have the same:

Nuclei with the same mass number but different atomic numbers are:

The energy of the Sun is produced mainly by:

In a nuclear reactor, the moderator is used to:

Isotones have the same number of:

Why is the mass of a nucleus less than the sum of the masses of its nucleons? (2 marks)

Why are very light and very heavy nuclei less stable than medium nuclei? (2 marks)

What is a chain reaction? How is it controlled in a reactor? (2 marks)

Write the relation E = mc^2 and explain its meaning. (2 marks)

Why is nuclear density so high compared to atomic density? (2 marks)

Name the materials used as moderator and control rods in a nuclear reactor. (2 marks)

Why is fusion called a thermonuclear reaction? (2 marks)

Give one example each of isotopes and isotones. (2 marks)

State two differences between nuclear force and electrostatic force. (2 marks)

Why is it difficult to achieve controlled fusion on Earth? (2 marks)

Find the radius of the nucleus of lead-208 (R0 = 1.2 fm, 208^(1/3) = 5.925). (3 marks)

Find the binding energy and binding energy per nucleon of the deuteron, given: mass of H-1 = 1.007825 u, neutron = 1.008665 u, deuteron (atom) = 2.014102 u. (3 marks)

Calculate the energy equivalent of 1 u in joules and MeV (1 u = 1.66 x 10^-27 kg, c = 3 x 10^8 m/s, 1 MeV = 1.6 x 10^-13 J). (3 marks)

Calculate the binding energy per nucleon of helium-4, given: He-4 atom = 4.002603 u, H-1 = 1.007825 u, neutron = 1.008665 u. (3 marks)

A 100 W lamp is powered by energy from U-235 fission (200 MeV per fission). How many fissions per second are needed? (3 marks)

Read the passage and answer the questions. A nuclear power reactor produces 1,000 MW of thermal power from fission of uranium-235. Each fission releases about 200 MeV. (i) Find the number of fissions per second. (ii) Find the mass of U-235 consumed per day. (iii) Why is enriched uranium used? (5 marks)

Read the passage and answer the questions. In the core of the Sun, at about 1.5 x 10^7 K, hydrogen nuclei fuse to form helium. The Sun loses about 4 x 10^9 kg of mass every second. (i) Name the process. (ii) Calculate the power radiated by the Sun using E = mc^2. (iii) Why is such a high temperature needed? (5 marks)

Read the passage and answer the questions. When a uranium-235 nucleus absorbs a slow neutron, it may split into barium-141 and krypton-92 with the release of three neutrons and energy. (i) Write the nuclear equation. (ii) Why are neutrons released? (iii) How can this lead to a chain reaction? (5 marks)

Read the passage and answer the questions. A student compares nuclei: 2H with binding energy per nucleon about 1.1 MeV, 4He about 7.1 MeV, 56Fe about 8.8 MeV and 238U about 7.6 MeV. (i) Which is the most stable? (ii) Why does fusing two 2H nuclei release energy? (iii) Why does splitting 238U release energy? (5 marks)

Read the passage and answer the questions. Carbon has isotopes 12C, 13C and 14C, while 14N and 14C have the same mass number. (i) What is common between 12C and 14C? (ii) What is the relation between 14C and 14N? (iii) Which pair of nuclei among these are isotones, if any? (5 marks)

Draw the binding energy per nucleon curve and explain its main features and their significance for nuclear stability, fission and fusion. (6 marks)

State the properties of nuclear force and draw the graph of potential energy between two nucleons against separation. (6 marks)

Explain nuclear fission with an example and equation. Explain the chain reaction and how it is controlled in a nuclear reactor, with a labelled diagram. (6 marks)

Explain nuclear fusion with an example. Why does it need high temperature? Describe the proton-proton cycle in the Sun briefly. (6 marks)

Derive the expression for nuclear radius and show that nuclear density is independent of mass number. Compare it with the density of water. (6 marks)