Energy from the Nucleus Problems
This section provides 100 problems to test your understanding of nuclear energy, including calculations of energy release in fission and fusion, nuclear reactor dynamics (e.g., fission rates, criticality), applications like RTGs and nuclear propulsion in spacecraft, and challenges such as radioactive waste decay. Inspired by JEE Main, JEE Advanced, and NEET exam patterns, these problems are tailored for exam preparation, offering a mix of numerical, conceptual, and derivation-based challenges. NEET-style problems (66–100) are formatted as multiple-choice questions (MCQs) to match the exam’s objective format. Problems are organized by type to support progressive learning and build confidence in mastering nuclear energy, a key topic for JEE/NEET success.
Numerical Problems
Calculate the Q-value of the fission reaction
in MeV. Given: , , , , . - (a) 173.2 MeV
- (b) 173.3 MeV
- (c) 173.4 MeV
- (d) 173.5 MeV
A nuclear reactor produces 2000 MW of thermal power. If each fission releases 200 MeV, calculate the number of fissions per second.
- (a)
- (b)
- (c)
- (d)
- (a)
Calculate the Q-value of the fusion reaction
in MeV. Given: , , , . - (a) 17.58 MeV
- (b) 17.59 MeV
- (c) 17.60 MeV
- (d) 17.61 MeV
An RTG using
( ) has an activity of 1000 Ci, with each decay releasing 5.5 MeV. Calculate the power output in Watts. - (a) 32.54 W
- (b) 32.55 W
- (c) 32.56 W
- (d) 32.57 W
A nuclear power plant produces 1200 MW of electrical power at 40% efficiency. Calculate the thermal power in MW.
- (a) 2999 MW
- (b) 3000 MW
- (c) 3001 MW
- (d) 3002 MW
High-level nuclear waste contains
( ) with an initial activity of 800 Ci. Calculate the time (in years) for the activity to reduce to 1 Ci. - (a) 299 years
- (b) 300 years
- (c) 301 years
- (d) 302 years
A spacecraft nuclear thermal propulsion (NTP) system produces 150 MW of thermal power, using
with each fission releasing 200 MeV. Calculate the fission rate in fissions per second. - (a)
- (b)
- (c)
- (d)
- (a)
Calculate the Q-value of the fusion reaction
in MeV. Given: , , . - (a) 3.26 MeV
- (b) 3.27 MeV
- (c) 3.28 MeV
- (d) 3.29 MeV
A nuclear plant produces 500 MW electrical power at 35% efficiency. Calculate the mass of
consumed per day (in kg), assuming 200 MeV per fission. Given: molar mass of . - (a) 0.96 kg
- (b) 0.97 kg
- (c) 0.98 kg
- (d) 0.99 kg
An RTG with
( ) has an initial activity of 200 Ci. Calculate the activity after 100 years in Ci. - (a) 61.5 Ci
- (b) 61.6 Ci
- (c) 61.7 Ci
- (d) 61.8 Ci
A reactor produces 4000 MW thermal power. If each fission releases 200 MeV, calculate the mass of
consumed per day (in kg). - (a) 1.92 kg
- (b) 1.93 kg
- (c) 1.94 kg
- (d) 1.95 kg
High-level waste with
( ) has an initial activity of 600 Ci. Calculate the activity after 50 years in Ci. - (a) 149 Ci
- (b) 150 Ci
- (c) 151 Ci
- (d) 152 Ci
A fusion reactor produces 1 GW using the D-T reaction (
). Calculate the fusion rate in fusions per second. - (a)
- (b)
- (c)
- (d)
- (a)
A nuclear plant produces 800 MW electrical power at 32% efficiency. Calculate the thermal power in MW.
- (a) 2499 MW
- (b) 2500 MW
- (c) 2501 MW
- (d) 2502 MW
An RTG with
( ) produces 50 W initially, with each decay releasing 5.5 MeV. Calculate the initial activity in Ci. - (a) 356 Ci
- (b) 357 Ci
- (c) 358 Ci
- (d) 359 Ci
A reactor with a fission rate of
fissions/s releases 200 MeV per fission. Calculate the thermal power in MW. - (a) 1599 MW
- (b) 1600 MW
- (c) 1601 MW
- (d) 1602 MW
High-level waste with
( ) has an initial activity of 1000 Ci. Calculate the time (in years) for activity to reduce to 10 Ci. - (a) 229 years
- (b) 230 years
- (c) 231 years
- (d) 232 years
A spacecraft NTP system produces 200 MW, heating hydrogen at 1 kg/s,
, , molar mass . Calculate exhaust velocity in m/s ( ). - (a) 8099 m/s
- (b) 8100 m/s
- (c) 8101 m/s
- (d) 8102 m/s
A fusion reactor produces 500 MW using D-T fusion (
). Calculate the mass of deuterium consumed per day (in kg), molar mass . - (a) 0.122 kg
- (b) 0.123 kg
- (c) 0.124 kg
- (d) 0.125 kg
A reactor produces 3000 MW thermal power. If each fission releases 200 MeV, calculate the mass of
consumed per day (in kg). - (a) 1.44 kg
- (b) 1.45 kg
- (c) 1.46 kg
- (d) 1.47 kg
High-level waste with
( ) has an initial activity of 400 Ci. Calculate the activity after 100 years in Ci. - (a) 36.0 Ci
- (b) 36.1 Ci
- (c) 36.2 Ci
- (d) 36.3 Ci
An RTG with
( ) produces 20 W, with each decay releasing 5.5 MeV. Calculate the initial activity in Ci. - (a) 142 Ci
- (b) 143 Ci
- (c) 144 Ci
- (d) 145 Ci
A nuclear plant produces 1500 MW electrical power at 38% efficiency. Calculate the thermal power in MW.
- (a) 3946 MW
- (b) 3947 MW
- (c) 3948 MW
- (d) 3949 MW
A reactor with a fission rate of
fissions/s releases 200 MeV per fission. Calculate the thermal power in MW. - (a) 6399 MW
- (b) 6400 MW
- (c) 6401 MW
- (d) 6402 MW
A fusion reactor produces 2 GW using D-T fusion (
). Calculate the fusion rate in fusions per second. - (a)
- (b)
- (c)
- (d)
- (a)
High-level waste with
( ) has an initial activity of 500 Ci. Calculate the activity after 200 years in Ci. - (a) 4.54 Ci
- (b) 4.55 Ci
- (c) 4.56 Ci
- (d) 4.57 Ci
A spacecraft NTP system produces 300 MW, heating hydrogen at 1.5 kg/s,
, , . Calculate exhaust velocity in m/s. - (a) 8348 m/s
- (b) 8349 m/s
- (c) 8350 m/s
- (d) 8351 m/s
A reactor produces 2500 MW thermal power. Calculate the mass of
consumed per day (in kg) if each fission releases 200 MeV. - (a) 1.20 kg
- (b) 1.21 kg
- (c) 1.22 kg
- (d) 1.23 kg
An RTG with
( ) has an initial activity of 300 Ci. Calculate the activity after 50 years in Ci. - (a) 168 Ci
- (b) 169 Ci
- (c) 170 Ci
- (d) 171 Ci
A nuclear plant produces 600 MW electrical power at 30% efficiency. Calculate the thermal power in MW.
- (a) 1999 MW
- (b) 2000 MW
- (c) 2001 MW
- (d) 2002 MW
A spacecraft fusion engine produces 1 GW,
. Calculate the mass of deuterium consumed per day (in kg), . - (a) 0.244 kg
- (b) 0.245 kg
- (c) 0.246 kg
- (d) 0.247 kg
High-level waste with
( ) has an initial activity of 1000 Ci. Calculate the time (in years) to reduce to 1 Ci. - (a) 191 years
- (b) 192 years
- (c) 193 years
- (d) 194 years
A reactor with a fission rate of
fissions/s releases 200 MeV per fission. Calculate the thermal power in MW. - (a) 3199 MW
- (b) 3200 MW
- (c) 3201 MW
- (d) 3202 MW
A nuclear plant produces 1800 MW electrical power at 36% efficiency. Calculate the thermal power in MW.
- (a) 4999 MW
- (b) 5000 MW
- (c) 5001 MW
- (d) 5002 MW
An RTG with
( ) has an initial activity of 150 Ci. Calculate the activity after 150 years in Ci. - (a) 29.9 Ci
- (b) 30.0 Ci
- (c) 30.1 Ci
- (d) 30.2 Ci
Conceptual Problems
What is the primary source of energy in nuclear fission?
- (a) Kinetic energy of neutrons
- (b) Increase in binding energy per nucleon in products
- (c) Decrease in mass number
- (d) Increase in atomic number
What is the role of control rods in a nuclear reactor?
- (a) Slow neutrons
- (b) Absorb neutrons to regulate reaction rate
- (c) Cool the reactor
- (d) Fuel the reactor
What is the unit of power output in a nuclear reactor in SI units?
- (a) Watt
- (b) Joule
- (c) Hertz
- (d) Becquerel
What happens to the reaction rate in a nuclear reactor if the multiplication factor
? - (a) Decreases
- (b) Increases exponentially
- (c) Remains constant
- (d) Becomes zero
What type of reaction powers the Sun?
- (a) Fission
- (b) Fusion
- (c) Alpha decay
- (d) Beta decay
What is the unit of Q-value in nuclear reactions?
- (a) MeV
- (b) Radian
- (c) Hertz
- (d) Watt
What does a high specific impulse in NTP indicate?
- (a) Low efficiency
- (b) High efficiency for propulsion
- (c) High mass consumption
- (d) Low thrust
What happens to nuclear waste activity over time?
- (a) Increases exponentially
- (b) Decreases exponentially
- (c) Remains constant
- (d) Becomes zero instantly
What is a major challenge of nuclear energy?
- (a) High CO
emissions - (b) Radioactive waste management
- (c) Low energy output
- (d) Fuel abundance
- (a) High CO
What is the dimension of
? - (a)
- (b)
- (c)
- (d)
- (a)
What does the moderator do in a nuclear reactor?
- (a) Absorbs neutrons
- (b) Slows neutrons to thermal energies
- (c) Increases reaction rate
- (d) Cools the reactor
What is the significance of
in a nuclear reactor? - (a) Critical state, steady reaction
- (b) Supercritical state
- (c) Subcritical state
- (d) Shutdown state
What happens to the efficiency of a nuclear power plant?
- (a) 100% due to high energy release
- (b) ~33–40% due to thermodynamic limits
- (c) 0% due to energy loss
- (d) Varies randomly
What does an RTG use to produce power?
- (a) Fission reactions
- (b) Fusion reactions
- (c) Decay heat from isotopes like
- (d) Chemical reactions
How does nuclear energy contribute to spacecraft propulsion?
- (a) Increases mass
- (b) Enables NTP and RTGs for efficient power and thrust
- (c) Reduces efficiency
- (d) Increases CO
emissions
Derivation Problems
Derive the Q-value
for a nuclear reaction. Derive the fission rate in a nuclear reactor given its thermal power output.
Derive the power output of an RTG given its activity and energy per decay.
Derive the time for nuclear waste to decay to a specific activity level.
Derive the thermal power in a nuclear reactor given the fission rate.
Derive the exhaust velocity in an NTP system
. Derive the mass of fuel consumed in a reactor given its power output.
Derive the activity
of nuclear waste after a given time . Derive the fusion rate in a reactor given its power output.
Derive the thermal power of a nuclear plant given its electrical power and efficiency.
Derive the Q-value for a fusion reaction.
Derive the mass of deuterium consumed in a fusion reactor.
Derive the time for an RTG's activity to decrease to a specific level.
Derive the fission rate in an NTP system given its power output.
Derive the efficiency
of a nuclear power plant given electrical and thermal power.
NEET-style Conceptual Problems
What is the unit of energy release
in nuclear reactions? - (a) MeV
- (b) Radian
- (c) Hertz
- (d) Watt
What does the reaction
represent? - (a) Fusion
- (b) Fission
- (c) Alpha decay
- (d) Beta decay
What is the relationship between thermal power and electrical power in a nuclear plant?
- (a)
- (b)
- (c)
is independent - (d)
- (a)
What happens to the activity of nuclear waste after one half-life?
- (a) Doubles
- (b) Halves
- (c) Remains the same
- (d) Becomes zero
What is the dimension of power output in a nuclear reactor?
- (a)
- (b)
- (c)
- (d)
- (a)
What does the coolant do in a nuclear reactor?
- (a) Slows neutrons
- (b) Transfers heat to produce steam
- (c) Absorbs neutrons
- (d) Fuels the reactor
What is the role of nuclear energy in spacecraft?
- (a) Increases CO
emissions - (b) Powers systems via RTGs and NTP
- (c) Reduces efficiency
- (d) Increases mass defect
- (a) Increases CO
What happens to the reaction rate in a reactor if
? - (a) Increases exponentially
- (b) Decreases and stops
- (c) Remains constant
- (d) Becomes infinite
Why does fusion require high temperatures?
- (a) To increase mass defect
- (b) To overcome Coulomb repulsion between nuclei
- (c) To reduce binding energy
- (d) To decrease reaction rate
What is the unit of activity in nuclear waste decay?
- (a) Curie (Ci)
- (b) Joule
- (c) Hertz
- (d) Watt
What does a high exhaust velocity in NTP indicate?
- (a) Low efficiency
- (b) High specific impulse
- (c) High mass consumption
- (d) Low power output
Which process produces less radioactive waste?
- (a) Fission
- (b) Fusion
- (c) Alpha decay
- (d) Beta decay
What is the effect of a nuclear accident like Fukushima?
- (a) Increases CO
emissions - (b) Radioactive contamination
- (c) Increases efficiency
- (d) Reduces waste
- (a) Increases CO
What does a pseudo-force do in a non-inertial frame for nuclear energy calculations?
- (a) Affects perceived reaction rate
- (b) Affects Q-value
- (c) Creates fusion
- (d) Reduces efficiency
What is the dimension of
? - (a)
- (b)
- (c)
- (d)
- (a)
What is the role of nuclear energy in desalination?
- (a) Increases CO
emissions - (b) Provides heat for water purification
- (c) Reduces efficiency
- (d) Increases waste
- (a) Increases CO
What happens to the energy release in fusion?
- (a) Decreases due to mass defect
- (b) Increases due to higher binding energy per nucleon
- (c) Remains the same
- (d) Becomes zero
Why are advanced reactors (Gen IV) being developed?
- (a) To increase CO
emissions - (b) To improve efficiency and reduce waste
- (c) To decrease safety
- (d) To increase proliferation
- (a) To increase CO
What is the significance of
in the D-T fusion reaction? - (a) Decay constant
- (b) Q-value of the reaction
- (c) Mass defect
- (d) Half-life
What is the unit of exhaust velocity
in NTP? - (a) m/s
- (b) Joule
- (c) Hertz
- (d) Watt
What does a high
value in a reactor indicate? - (a) Stable operation
- (b) Potential for uncontrolled reaction
- (c) Shutdown state
- (d) Low efficiency
What is the physical significance of
in waste decay? - (a) Q-value
- (b) Exponential decrease in activity
- (c) Mass defect
- (d) Fission rate
Why is nuclear energy considered low-carbon?
- (a) Due to high CO
emissions - (b) Due to minimal greenhouse gas emissions
- (c) Due to high waste production
- (d) Due to low efficiency
- (a) Due to high CO
What is the dimension of
in RTG power calculation? - (a)
- (b)
- (c)
- (d)
- (a)
How does fusion energy aim to impact future energy production?
- (a) Increases waste
- (b) Provides a clean, limitless energy source
- (c) Reduces safety
- (d) Increases CO
emissions
What is the role of thermocouples in an RTG?
- (a) Increase decay rate
- (b) Convert heat to electricity
- (c) Absorb neutrons
- (d) Cool the system
What does a low efficiency in nuclear plants indicate?
- (a) High thermal power
- (b) Thermodynamic limitations
- (c) High electrical power
- (d) No energy loss
What is the physical significance of
? - (a) Mass defect
- (b) Reaction rate in a reactor
- (c) Decay constant
- (d) Efficiency
What is the dimension of
? - (a)
- (b)
- (c)
- (d)
- (a)
Why are nuclear plants efficient for large-scale energy?
- (a) Due to high CO
emissions - (b) Due to high energy density of nuclear fuel
- (c) Due to low output
- (d) Due to high waste
- (a) Due to high CO
NEET-style Numerical Problems
Calculate the Q-value of
in MeV. Given: , , , . - (a) 185.1 MeV
- (b) 185.2 MeV
- (c) 185.3 MeV
- (d) 185.4 MeV
A nuclear reactor produces 1000 MW thermal power. If each fission releases 200 MeV, calculate the fission rate in fissions per second.
- (a)
- (b)
- (c)
- (d)
- (a)
An RTG with
( ) has an initial activity of 400 Ci. Calculate the activity after 100 years in Ci. - (a) 123.2 Ci
- (b) 123.3 Ci
- (c) 123.4 Ci
- (d) 123.5 Ci
A nuclear plant produces 900 MW electrical power at 34% efficiency. Calculate the thermal power in MW.
- (a) 2646 MW
- (b) 2647 MW
- (c) 2648 MW
- (d) 2649 MW
A spacecraft NTP system produces 250 MW, heating hydrogen at 2 kg/s,
, , . Calculate exhaust velocity in m/s.
- (a) 8224 m/s
- (b) 8225 m/s
- (c) 8226 m/s
- (d) 8227 m/s