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प्रश्न
What is meant by radioactivity?
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उत्तर
Elements with a high atomic number such as uranium, thorium, radium have a property of spontaneously emitting invisible, highly penetrating and high energy radiation. This property is called radioactivity. The nucleus of radioactive elements is unstable.
संबंधित प्रश्न
Name the radiations which are absorbed by greenhouse gases in the earth’s atmosphere.
A radiation X is focused by a particular device on the bulb of a thermometer and mercury in the thermometer shows a rapid increase. Name the radiation X
Answer the following questions based on a hot cathode ray tube.
What will happen to the beam when it passes through the electric field?
State three factors on which the rate of emission of electrons from a metal surface depends
Represent the change in the nucleus of a radioactive element when a β particle is emitted.
State any two precautions to be taken while handling radioactive substances.
In a cathode ray tube state:
(i) the purpose of covering cathode by thorium and carbon.
(ii) the purpose of the fluorescent screen.
(iii) how is it possible to increase the rate of emission of electrons.
Radiations given out from a source when subjected to an electric field in a direction perpendicular to their path are shown below in the diagram. The arrows show the path of the radiation A, B and C. Answer the following questions in terms of A, B and C.
1) Name the radiation B which is unaffected by the electrostatic field.
2) Why does the radiation C deflect more than A?
3) Which among the three causes the least biological damage externally.
4) Name the radiation which is used in carbon dating.
What happens to the atomic number of element when (i) An α -particle, (ii) A β -particle 1 and (iii) γ-radiation is emitted?
Define the term radioactivity.
Draw a diagram of a simple atom showing the nucleus and electrons. In this atom:
(a) What type of charge will there be on the nucleus?
(b) What is the value of this charge?
A nucleus of an element X which has the symbol `""_84^202` X emits an alpha particle and then a beta particle. The final nucleus is `""_"b"^"a"` Y Find a and b.
Why should a radioactive substance not be touched by hands?
Define free electrons.
How is a cathode ray beam affected while passing through an electric field?
In a cathode ray tube state the purpose of the fluorescent screen.
Name the three main parts of a Cathode Ray Tube.
How is a cathode ray tube used to convert an electrical signal into a visual signal?
What is meant by Radioactivity?
Heavy radioactive elements eventually turn into ______.
Two radioactive sources A and B of half lives of 1 hour and 2 hours, respectively, initially contain the same number of radioactive atoms. At the end of two hours, their rates of disintegration are in the ratio of ______.
A radioactive element is placed in an evacuated chamber. Then the rate of radioactive decay will ______.
In the following atoms, which one is a radioisotope? Give one use of this isotope.
O16, C14, N14, He4
Assertion (A): Hydrogen atom consists of only one electron but its emission spectrum has may lines.
Reason (R): Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.
While investigating which phenomena was Becquerel studying uranium salts when he discovered radioactivity?
In beta decay, what particles can the nucleus emit?
Which of the following correctly lists the three major types of radioactive decay found in nature?
