This set of Cell Biology Multiple Choice Questions & Answers (MCQs) focuses on “Techniques – Use of Radioisotopes”.
1. The identity and chemical properties of an atom are determined by ____________
a) critical temperature
b) critical freezing point
c) melting temperature
d) number of protons
Explanation: The identity and chemical properties of a compound can be determined by the number of positively charged protons it contains. For example, hydrogen has a single proton and helium has two.
2. Isotopes have the same number of protons.
Explanation: The isotopes have same number of protons but different number of neutrons in their nucleus. Hydrogen has three isotopes depending on the number of neutrons – 0, 1 or 2.
3. Which of the following is radioactive?
a) hydrogen sulfide
Explanation: Depending on the number of neutrons present, the hydrogen has three isotopes. Deuterium and tritium are its isotopes, out of which tritium contains two neutrons and is radioactive.
4. The half life of a radioisotope is _____________
a) half the time taken for complete decay
b) half the time taken for half the decay
c) time taken for complete decay
d) time taken for half the decay
Explanation: Half life of any radioisotope or radioactive element is the time taken for half of the atoms to undergo complete decay. The formula to find half-life is given by N(t) = N0e−λt.
5. Which of the following emitted particles consists of two protons?
Explanation: Three different types of emissions are possible for an atom that is disintegrating. One type of particles that may be released is the alpha particle that consists of two protons and two neutrons (equivalent to the nucleus of a helium atom).
6. A beta particle is equivalent to an electron.
Explanation: By disintegration of an atom, an alpha particle, beta particle or a gamma radiation may be emitted. Beta-particle is equivalent to an electron while the gamma radiation is the emission of photons.
7. Liquid scintillation spectrometry is a method of detecting ________________________
Explanation: Liquid scintillation spectrometry is a method of detecting the beta-emitters during disintegration of an atom. The technique is based on certain compounds termed phosphors that some of the energy of emitted particles and release it in the form of light.
Sanfoundry Global Education & Learning Series – Cell Biology.
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