# Energetics of Nuclear Fission

## Trending Questions

**Q.**The following figure represents the liquid drop model of nuclear fission. The energies of these states are E1, E2 and E3 respectively. Which option is correct?

- E1>E2<E3
- E1>E2>E3
- E1<E2<E3
- E1<E2>E3

**Q.**Statement I: Nuclear fission is not a spontaneous process as the energy is required to be supplied to it to reach the intermediate state before breaking up into two fragments.

Statement II: The energy of the intermediate state is higher than the initial energy of the parent nucleus.

- Both the statements are correct and statement II infers to statement I
- Both the statements are correct but statement II doesn’t infer to statement I
- Statement I is correct but statement II is incorrect
- Statement II is correct but statement I is incorrect

**Q.**In the given radioactive disintegration series,

23592U→20782Pb

Calculate the difference between the number of α and β particles emitted in this series.

**Q.**15. The radio active " Sr that is formed due to nuclear explosion has half life { period of 28.1 years. In the body of a child born at this time 90Sr is found to { be 10^{-6 gram, then what will be ^{90Sr destroyed from the body of child when the { age of the child will be 30 years.

**Q.**A heavier unstable nucleus breaks into two fragments of comparable mass in a nuclear fission reaction and energy is released because:

- The total rest mass energy of the two fragments is less than the rest mass energy of the heavy nucleus.
- The binding energy per nucleon of the two fragments is more than the binding energy per nucleon of the heavy nucleus.
- The nuclei of the fragments are more bound than the nucleus of the parent.
- NONE OF THE ABOVE

**Q.**Liquid hydrogen is used as a fuel for rocket propulsion.

- True
- False

**Q.**Statement I : Nuclear fission is a spontaneous process, i.e., there is no need of external energy supply for this to happen.

Statement II : In a nuclear fission reaction, the rest mass energy of the parent nucleus is more than the combined rest mass energy of two daughter fragments and neutrons.

- Statement II is correct but statement I is incorrect
- Statement I is correct but statement II is incorrect
- Both the statements are correct and statement II infers to statement I
- Both the statements are correct but statement II doesn’t infer to statement I

**Q.**Assume a hypothetical nuclear fission reaction:

X→Y+Z

If the atomic masses of X, YandZ are respectively x, yandz calculate the maximum amount of heat generated if 1gramof X undergoes fission. Consider the molar mass of X to be M.

- NAM×(y−z−x)c2units
- NAM×(x−y−z)c2units
- NAM×(x−y+z)c2units
- M×(x−y−z)c2units

**Q.**A heavier unstable nucleus breaks into two fragments of comparable mass in a nuclear fission reaction and energy is released because:

- The total rest mass energy of the two fragments is less than the rest mass energy of the heavy nucleus.
- The binding energy per nucleon of the two fragments is more than the binding energy per nucleon of the heavy nucleus.
- The nuclei of the fragments are more bound than the nucleus of the parent.
- NONE OF THE ABOVE

**Q.**The activity of the radioactive sample drops to 1 / 64 of its original value in 2 hr find the decay constant ?(λ).

- (λ)=1.079hr−1
- (λ)=2.579hr−1
- (λ)=1.579hr−1
- (λ)=2.079hr−1

**Q.**Which of the following ratio will give stability to daughter element, when radioactive parent element has less number of protons compared to number of neutrons?

- N+1Z+1
- N−1Z+1
- N−1Z−1
- N+1Z−1

**Q.**The half life of a radioactive isotope is 3 hours. What is the value of its disintegration constant?

- 0.231min−1
- 0.231hour−1
- 0.3hour−1
- 0.693hour−1

**Q.**Shown here are the steps of nuclear fission using the liquid drop model. Which of these is the correct sequence?

- b, c, a
- b, a, c
- c, b, a
- a, b, c

**Q.**In the given radioactive disintegration series,

23592U→20782Pb

Calculate the difference between the number of α and β particles emitted in this series.

**Q.**A radioactive isotope is being produced at a constant rate of dN/dt=R in an experiment. The isotope has a half-life of t1/2. After a time t>>t1/2, the number of active nuclei will become constant. The value of this constant is :

- R
- 1
- R/λ
- λ/R

**Q.**A radioactive sample had an initial activity of 56 DPM ( disintegration per min ). After 69.3 min, it was found to have an activity of 28 DPM. Find the number of atoms in a sample having an activity of 10 DPM.

- 693
- 1000
- 100
- 10, 000

**Q.**After 20 min, the amount of certain radioactive substance disintegrate was (15/16)th of the original amount.

What is the half-life of the radioactive substance?

- 7
- 4
- 5
- 10

**Q.**The unit for nuclear dose given to a patient is

- Fermi
- Rutherford
- Curie
- Roentgen

**Q.**The disintegration rate for a sample containing 6027Co as the only radioactive nuclide, is found to be 240 atoms/ minute. t1/2 of Co is 5.2 years. Find the number of atoms of Co in the sample. How long must this radioactive sample be maintained before the rate falls to 100 disintegration / minute.

**Q.**Shown here are the steps of nuclear fission using the liquid drop model. Which of these is the correct sequence?

- b, c, a
- c, b, a
- a, b, c
- b, a, c

**Q.**m g of a radioactive species (atomic mass M) has decay constant λ. The initial specific activity at zero time is given by :

- λNAM
- λNAmM
- λmM
- mMeλ

**Q.**Concentration of the radioactive element after one average life is _________ of the original concentration.

- 12
- 1e
- 1e2
- none of these

**Q.**Assertion :In radioactive disintegrations, 2He4 nuclei can come out of the nucleus but lighter 2He3 can't. Reason: Binding energy of 2He3 is more than that of 2He4.

- Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
- Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
- Assertion is correct but Reason is incorrect
- Both Assertion and Reason are incorrect

**Q.**In the given radioactive disintegration series,

23592U→20782Pb

Calculate the difference between the number of α and β particles emitted in this series.

**Q.**In the following disintegration

23892U⟶20682Pb+.......

number of β-particles emitted is

- 6
- 4
- 5
- None of these

**Q.**In the nuclear change ${}_{92}\mathrm{U}^{235}+{}_{0}n^{1}$ → Fission products + neutron + 3.20 × 10

^{–11}J, the energy released when 1 g of ${}_{92}\mathrm{U}^{235}$ finally undergoes fission is

(a) 12.75 × 10

^{8}kJ (b) 18.60 × 10

^{9}kJ (c) 8.21 × 10

^{7}kJ (d) 6.55 × 10

^{6}kJ