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Class 12 Nuclei worksheet
CBSE Physics. Nuclear size and density, mass defect, binding energy, fission and fusion. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The radius of a nucleus of mass number 1 is: (R₀ = 1.2 fm)
- 0.6 fm
- 2.4 fm
- 2.2 fm
- 1.2 fm
Answer
(d) 1.2 fm
R = R₀A^(1/3) = 1.2 × 1
- 2.
The ratio of the radii of nuclei of mass numbers 216 and 125 is:
- 216 : 125
- 5 : 6
- 6 : 5
- 46656 : 15625
Answer
(c) 6 : 5
R ∝ A^(1/3)
- 3.
The mass defect of a nucleus is 0.01422 u. Its binding energy is: (1 u = 931.5 MeV)
- 6.62 MeV
- 0.13 MeV
- 132.46 MeV
- 13.25 MeV
Answer
(d) 13.25 MeV
BE = Δm × 931.5 MeV
Section B · short answer
- 4.
The mass of the ⁴⁰₂₀Ca nucleus is 39.9874 u. Find its mass defect, binding energy and binding energy per nucleon. (m_p = 1.00728 u, m_n = 1.00867 u, 1 u = 931.5 MeV)
Answer
Δm = 0.3316 u; BE = 308.89 MeV; 7.72 MeV per nucleon
Δm = 20 × 1.00728 + 20 × 1.00867 − M
- 5.
How much energy is equivalent to 1 g of mass? How many kWh is that? (c = 3 × 10⁸ m/s)
Answer
9 × 10¹³ J; 2.5 × 10⁶ kWh
E = mc² = 1 × 10⁻³ × 9 × 10¹⁶; 1 kWh = 3.6 × 10⁶ J
Section C · long answer
- 6.
Find the binding energy and binding energy per nucleon of ¹⁴₇N, whose nuclear mass is 13.98859 u. Is it more or less tightly bound than ⁵⁶Fe (8.8 MeV per nucleon)? (m_p = 1.00728 u, m_n = 1.00867 u, 1 u = 931.5 MeV)
Answer
Δm = 0.12306 u; BE = 114.63 MeV; 8.19 MeV per nucleon; less tightly bound
BE = [Zm_p + Nm_n − M] × 931.5
Fresh sheets for your child
In the app, every Nuclei sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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