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प्रश्न
In a cathode ray tube state. How is it possible to increase the rate of emission of electrons.
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उत्तर
(i) Decrease work function.
(ii) Coating the cathode with a layer of alkaline earth metallic oxides (or) hydrides.
संबंधित प्रश्न
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.
Radioactive substances were found to give off three types of rays. Name them. How do they
(a) React to the magnetic field?
(b) React to the electric field?
(c) Act when different thickness of lead sheets is placed in their path?
A radioactive source emits three types of radiations.
Name the radiation which has the highest ionizing power.
What happens to the position of an element in the periodic table when it emits an alpha particle
How is a cathode ray beam affected while passing through a magnetic field?
In a cathode ray tube state the purpose of the fluorescent screen.
Justify with reason, whether the following nuclear reactions are allowed or not.
\[\ce{^A_Z X -> ^A_{Z + 1}Y + ^0_{-1}β}\]
Two radioactive nuclei are represented by xAp and yAq and when p and q are mass numbers and x, y are the atomic number. How can the products be represented, i .e., what are the new values of p, q. x and y after the emission of an α-particle and a β-particle from A and B respectively.
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)
When an α-particle of mass m moving with velocity ν bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on m as:
