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Question
What do you understand by the term radioactivity?
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Solution
The process of self, spontaneous and random emission of a or P and y radiations from the nucleus of elements of atomic number higher than 82, is called radioactivity.
RELATED QUESTIONS
Arrange α, β, and γ rays in ascending order with respect to their
1) Penetrating power.
2) Ionising power
3) Biological effect
Write one use of cathode ray tube.
Why is a cathode ray tube evacuated to a low pressure?
A radioactive source emits three types of radiations. Name them.
(i) Name the radiations which are charged.
(ii) Name the radiations which are most penetrating.
(iii) Name the radiations which travel with the speed of light.
(iv) Name the radiations which have the largest mass.
A radioactive nuclide `""_86^226` Ra decays by emission of two alpha particles, one beta particle and gamma rays. Which of the following is the resulting nuclide X?
An element P disintegrates by α - -emission and the new element suffers two further disintegrations, both by β -emission, to form an element Q. Explain the fact that P and Q are the isotopes.
What are cathode rays? Why are they called ‘cathode rays’? Name a material which exhibits fluorescence when cathode rays fall on it.
The mean lives of a radioactive substance are 1620 and 405 years for β-emission and β-emission respectively. The time after which three fourth of a sample will decay if it is decaying both by β-emission and β-emission simultaneously will be ______ years.
(Take ln 2 = 0.693)
Complete the following radioactive reaction:
\[\ce{^-_-X -> ^-_-Y + ^4_2He -> ^234_91Z + ^0_-1e}\]
Assertion (A): The force of repulsion between atomic nucleus and α-particle varies with distance according to inverse square law.
Reason (R): Rutherford did α-particles scattering experiment.
