P.3.8.1.6 Mass and Energy

A deuterium nucleus and a tritium nucleus fuse together to form a helium nucleus and a particle X. The equation for this process is:

What is X?

• electron

• neutron

• positron

• proton

During a single fission event of uranium-235 in a nuclear reactor the total mass lost is 0.23 u. The reactor is 25% efficient.

How many events per second are required to generate 900 MW of power?

• 1.1 × 10¹⁴

• 6.6 × 10¹⁸

• 1.1 × 10²⁰

• 4.4 × 10²⁰

Uranium-236 undergoes nuclear fission to produce barium-144, krypton-89 and three free neutrons.

What is the energy released in this process?

• 84 MeV

• 106 MeV

• 191 MeV

• 3730 MeV

The power output of a nuclear reactor is provided by nuclear fuel which decreases in mass at a rate of 4.0 × 10⁻⁶ kg hour⁻¹.

What is the maximum possible power output of the reactor?

• 28 kW

• 50 MW

• 100 MW

• 200 MW

The graph shows how the binding energy per nucleon varies with the nucleon number for stable nuclei.

What is the approximate total binding energy for a nucleus of ¹⁸⁴₇₄W?

• 1.28 pJ

• 94.7 pJ

• 103 pJ

• 230 pJ

In the reaction shown, a proton and a deuterium nucleus, ²₁H, fuse together to form a helium nucleus, ³₂He

What is the value of Q, the energy released in this reaction?

mass of a proton = 1.00728 u

mass of a ²₁H nucleus = 2.01355 u

mass of a ³₂He nucleus = 3.01493 u

• 5.0 MeV

• 5.5 MeV

• 6.0 MeV

• 6.5 MeV

The mass of the beryllium nucleus, ⁷₄Be , is 7.01473 u. What is the binding energy per nucleon of this nucleus?

Use the following data:

mass of proton = 1.00728 u

mass of neutron = 1.00867 u

1u = 931.3 MeV

• 1.6 MeV nucleon⁻¹

• 5.4 MeV nucleon⁻¹

• 9.4 MeV nucleon⁻¹

• 12.5 MeV nucleon−1

The fusion of two deuterium nuclei produces a nuclide of helium plus a neutron and liberates 3.27 MeV of energy. How does the mass of the two deuterium nuclei compare with the combined mass of the helium nucleus and neutron?

• It is 5.8 × 10⁻³⁰ kg greater before fusion.

• It is 5.8 × 10⁻³⁰ kg greater after fusion.

• It is 5.8 × 10⁻³⁶ kg greater before fusion.

• It is 5.8 × 10⁻³⁶ kg greater after fusion.

The mass of the nuclear fuel in a nuclear reactor decreases at a rate of 1.2 × 10⁻⁵ kg per hour.

Assuming 100% efficiency in the reactor what is the power output of the reactor?

• 100 MW

• 150 MW

• 200 MW

• 300 MW

What is the binding energy of the nucleus ²³⁸₉₂U?

Use the following data:

mass of a proton =1.00728 u

mass of a neutron = 1.00867 u

mass of a ²³⁸₉₂U nucleus = 238.05076 u

1 u = 931.3 MeV

• 1685 MeV

• 1732 MeV

• 1755 MeV

• 1802 MeV