Get premium membership and access questions with answers, video lessons as well as revision papers.
Radioactivity or radioactive decay is the spontaneous disintegration of unstable nuclides to form stable ones with the emission of radiation. Unstable nuclides continue to disintegrate until a stable atom is formed.
Alpha (${\alpha}$) and beta (${\beta}$) particles are emitted and the gamma rays (${\gamma}$) accompany the ejection of both alpha and beta particles.
johnmulu answered the question on February 21, 2017 at 13:46
- Define half-life of a radioactive material. (Solved)
Define the term half-life of a radioactive material.
Date posted: February 21, 2017. Answers (1)
- A radioactive nuclide of atomic number Z emits a beta particle and gamma rays. State the atomic number of the nuclide.(Solved)
A radioactive nuclide of atomic number Z emits a beta particle and gamma rays. State the atomic number of the nuclide.
Date posted: February 21, 2017. Answers (1)
- In a sample there are 5.12 x 1020 atoms of krypton -92 initially. If the half-life of krypton-92 is 3.0 s, determine the number of atoms that will have decayed after 6 s.(Solved)
In a sample there are 5.12 x 1020 atoms of krypton -92 initially. If the half-life of krypton-92 is 3.0 s, determine the number of atoms that will have decayed after 6 s.
Date posted: February 21, 2017. Answers (1)
- State factors that affect photoelectric emission(Solved)
State factors that affect photoelectric emission.
Date posted: February 21, 2017. Answers (1)
- State one application of thermionic emission.(Solved)
State the applications of thermionic emission.
Date posted: February 21, 2017. Answers (1)
- It is observed that when the cap of an uncharged electroscope is irradiated with light of high frequency, the leaf of electroscope rises. Explain this observation (Solved)
It is observed that when the cap of an uncharged electroscope is irradiated with light of high frequency, the leaf of electroscope rises. Explain this observation
Date posted: February 21, 2017. Answers (1)
- A photo of ultraviolet light having energy E falls on a photo emissive surface whose work function is T. Write an expression for maximum kinetic energy of the resulting photoelectron in terms of E and T. (Solved)
A photo of ultraviolet light having energy E falls on a photo emissive surface whose work function is T. Write an expression for maximum kinetic energy of the resulting photoelectron in terms of E and T.
Date posted: February 21, 2017. Answers (1)
- Light of frequency 7.5 x 1014Hz strikes a metal surface whose work function is 4.0 x 10-19 J. Determine the kinetic energy of the emitted photoelectrons. (Solved)
Light of frequency 7.5 x 1014Hz strikes a metal surface whose work function is 4.0 x 10-19 J. Determine the kinetic energy of the emitted photoelectrons. (take planks constant h = 6.63 x 10-34Js)
Date posted: February 21, 2017. Answers (1)
- Define the term "threshold frequency" as used in photo electric emission.(Solved)
State the meaning of the term "threshold frequency" as used in photo electric emission.
Date posted: February 21, 2017. Answers (1)
- What is meant by stopping potential?(Solved)
What is meant by stopping potential?
Date posted: February 21, 2017. Answers (1)
- State the property of radiation that determines the number of electrons emitted when a radiation falls on a metal surface. (Solved)
State the property of radiation that determines the number of electrons emitted when a radiation falls on a metal surface.
Date posted: February 21, 2017. Answers (1)
- If the frequency of the illuminating radiation is just equal to the threshold frequency of the surface explain why no photoelectric effect is observed . (Solved)
If the frequency of the illuminating radiation is just equal to the threshold frequency of the surface explain why no photoelectric effect is observed .
Date posted: February 21, 2017. Answers (1)
- What is meant by the term work function? (Solved)
What is meant by the term work function?
Date posted: February 21, 2017. Answers (1)
- Explain how an "excited" hydrogen atom is able to emit radiations of different wavelengths(Solved)
Explain how an "excited" hydrogen atom is able to emit radiations of different wavelengths
Date posted: February 21, 2017. Answers (1)
- What is photoelectric effect?(Solved)
What is photoelectric effect?
Date posted: February 21, 2017. Answers (1)
- The work function of a certain material is 3.2 eV. Determine the threshold frequency for the material. (1 electron Volt(eV) = 1.6 x 10-19 J and planks Constant h = 6.62 x 10-34Js)(Solved)
The work function of a certain material is 3.2 eV. Determine the threshold frequency for the material. (1 electron Volt(eV) = 1.6 x 10-19 J and planks Constant h = 6.62 x 10-34Js)
Date posted: February 21, 2017. Answers (1)
- The minimum frequency of radiation necessary to cause photoelectric effect on a certain metal surface in 9.06 x 1014Hz. Determine the work function of the metal.(Solved)
The minimum frequency of radiation necessary to cause photoelectric effect on a certain metal surface in 9.06 x 1014Hz. Determine the work function of the metal. (Plank constant h = 6.63 x 10-19Js)
Date posted: February 21, 2017. Answers (1)
- Light of a certain wavelength strikes the surface of a metal. State what determines the maximum kinetic energy of the electron emmitted. (Solved)
Light of a certain wavelength strikes the surface of a metal. State what determines the maximum kinetic energy of the electron emmitted.
Date posted: February 20, 2017. Answers (1)
- It is observed that when ultraviolet light is shone onto a clean zinc plate connected to the cap of negatively charged leaf electroscope, the leaf collapses(Solved)
It is observed that when ultraviolet light is shone onto a clean zinc plate connected to the cap of negatively charged leaf electroscope, the leaf collapses. Explain this observation
Date posted: February 20, 2017. Answers (1)
- The anode of an x-ray tube becomes hot when the tube is in use. State the reason for this.(Solved)
The anode of an x-ray tube becomes hot when the tube is in use. State the reason for this.
Date posted: February 20, 2017. Answers (1)