Law of Radioactivity by Rutherford and Soddy and Half Life and Mean Life PYQs: JEE Mains Physics – Page 2

Showing 51–55 of 55 questions

51. 51. A piece of bone of an animal from a ruin is found to have \(^{14}C\) activity of \(12\) disintegrations per minute per gm of its carbon content. The \(^{14}C\) activity of a living animal is \(16\) disintegrations per minute per gm. How long ago nearly did the animal die? ............\(years\) (Given halflife of \(^{14}C\) is \(t_{1/2} = 5760\,years\) ) 2014 Medium
52. 52. A piece of wood from a recently cut tree shows \(20\,decays\) per minute. A wooden piece of same size placed in a museum ( obtained from a tree cut many years back) shows \(2\,decays\) per minute. If half life of \(C^{14}\) is \(5730\, years\), then age of the wooden piece placed in the museum is approximately ........... \(years\) 2014 Hard
53. 53. A radioactive nuclei with decay constant \(0.5/s\) is being produced at a constant rate of \(100\, nuclei/s\). If at \(t\, = 0\) there were no nuclei, the time when there are \(50\, nuclei\) is 2014 Hard
54. 54. Match List \(I\) (Wavelength range of electromagnetic spectrum) with List \(II\) (Method of production of these waves) and select the correct option from the options given below the lists

    List \(I\)	List \(II\)
    \((1)\) \(700\, nm\) to \(1\,mm\)	\((i)\) Vibration of atoms and molecules
    \((2)\) \(1\,nm\) to \(400\, nm\)	\((ii)\) Inner shell electrons in atoms moving from one energy level to a lower level
    \((3)\) \( < 10^{-3}\,nm\)	\((iii)\) Radioactive decay of the nucleus
    \((4)\) \(1\,mm\) to \(0.1\,m\)	\((iv)\) Magnetron valve

    2014 Medium
55. 55. The half-life of a radioactive element \(A\) is the same as the mean-life of another radioactive element \(B.\) Initially both substances have the same number of atoms, then 2013 Medium

No questions on this page match these filters. Clear filters