Atomic and Nuclear Physics Answers

Electromagnetic radiation of frequency 9.0 x 10^14Hz is incident on a clean metal surface. The work function of the metal is 5.0 x 10^-19J. Determine the maximum kinetic energy of photoelectrons released from the metal surface

Calculate the velocity of an electron emitted by radiation of frequency 5.7 x 10^14Hz from a surface with a work function of 3.18 x 10^-19J

If sodium is irradiated with light of 439nm, determine the maximum possible kinetic energy of the emitted electrons in eV

One major limitation of X-Ray Machine is

A. Thermionic emission. B. Low emission. C. Energy loss by scattering. D. Heat Generation. E. Excitation process

The following set of nuclides (₆¹³C,¹⁴_{7 N,} ¹⁷₈O, and ³⁷₁₇C) are

A. Isotopes B. Isotones C. Undefined. D. Isobars. E. Isohel

1. Describe two possible mechanisms by which ¹¹𝑁𝑎₂₂ could decay to ¹¹𝑁𝑒₂₂

2. (a) Write a shorthand nuclear reaction equation of the following equation;

₂𝐻_𝑒⁴ + ₇𝑁¹₄ → ⁸𝑁¹₇ + ₁𝐻¹

(b) Consider the following nuclear reaction equation; ₅𝐵¹₀ + ₂𝐻_𝑒⁴ → ₆𝐶¹₃ + ₁𝐻¹

(i) Calculate the Q - value for this reaction.

(ii) What can you deduce from the results of the Q – value?

(iii) Is this reaction energetically possible? Why?

3. When a neutron and a proton combine, a nucleus deuteron is formed in the process. A photon of 2.22MeV energy can disintegrate the deuteron into its components. What is the mass of the deuteron?

4. (a) Distinguish between nuclear fission and nuclear fusion, giving examples.

(b) Why do these reactions produce vast quantities of energy?

(c) Which of them has been applied for peaceful purposes as well as destructive purposes?

(d) Why has the other not been applied for peaceful purposes yet?

(e) Describe a ‘chain reaction’ and explain how it occurs.

A given radioactive parent has decay constant 𝜆₁ and at time t = 0 there are 𝑁¹₀ parent nuclei and the number of radioactive daughter nuclei is 𝑁²₀ = 0. The daughter has decay constant 𝜆₂. Show;

(i) that the number of daughter nuclei 𝑁₂ at time t > 0 is N₂ = 𝑁²₀ (𝜆₁/𝜆₂ − 𝜆₁) (𝑒^𝜆1𝑡− 𝑒^𝜆2𝑡).

(ii) The value of N₂ is zero at t = 0 and at t = ∞ . It therefore passes through a maximum at some time tm. Show that tm is given by t_m = 𝜏₂(𝑇₁/𝑇₁ − 𝑇₂) In[𝑇₁/𝑇₂] where T₁ and T₂ are the half – lives of the parent and the daughter respectively, and 𝜏2 is the mean life of the daughter