NEET Atoms and Nuclei — Set 14

Question 1

What is the ratio of nuclear radii of nuclei with mass numbers 125 and 27?

Accepted Answer

Radius ratio = $ \frac{R_1}{R_2} = \left( \frac{A_1}{A_2} \right)^{1/3} $. $ A_1 = 125 $, $ A_2 = 27 $. $ \frac{125}{27} \approx 4.63 $, $ (4.63)^{1/3} \approx 1.67 $.

Question 2

What does the mass defect of a nucleus represent?

Accepted Answer

The mass defect is the difference between the total mass of the individual protons and neutrons and the actual mass of the nucleus, representing the mass converted into binding energy that holds the nucleus together.

Question 3

Why does nuclear fission release more energy than chemical reactions?

Accepted Answer

Nuclear fission involves changes in nuclear binding energy (order of MeV), which is about a million times larger than the energy from chemical bond changes (order of eV).

NEET Physics: Atoms and Nuclei — Practice Set 14

Q1. What is the ratio of nuclear radii of nuclei with mass numbers 125 and 27?

Q2. What does the mass defect of a nucleus represent?

Q3. Why does nuclear fission release more energy than chemical reactions?

Q4. What is the energy equivalent of \( 0.02 \, \text{kg} \) of matter in Joules? (Given \( c = 3 \times 10^8 \, \text{m/s} \))

Q5. What is the primary reason nuclear reactions release more energy than chemical reactions?

Q6. Which force is responsible for overcoming the repulsion between protons in the nucleus?

Q7. What is the ratio of nuclear radii of two nuclei with mass numbers 64 and 8?

Q8. Why does the binding energy per nucleon remain nearly constant for nuclei with mass numbers between 30 and 170?

Q9. What is the nuclear density of a nucleus with mass \( 2.33 \times 10^{-27} \, \text{kg} \) and radius \( 1.7 \times 10^{-15} \, \text{m} \)? (Use \( \pi = 3.14 \))

Q10. What is the outcome when two light nuclei fuse into a heavier nucleus?