Advertisements
Advertisements
प्रश्न
An electromagnetic radiation is used for photography in fog. [2]
(i) Identify the radiation.
(ii) Why is this radiation mentioned by you, ideal for this purpose ?
Advertisements
उत्तर
(i) Infared radiation.
(ii) They have low frequency, the energy associated with them is also low so they do not scatter much and can penetrate appreciably through it.
APPEARS IN
संबंधित प्रश्न
Why do Free electrons not leave the metal surface on their own
What are isobars?
In the following fig. shows a radioactive source S in a thick lead container. The radiations pass through an electric field between the plates P and Q. Complete the diagram to show the paths of α , β and γ radiations.
Why is the source S placed in a thick lead container?
Define the term radioactivity.
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.
State two properties that a substance should possess when used as a thermionic emitter.
Name a common device where a hot cathode ray tube is used.
Are all the radiations viz. α, β and γ emitted in a single radioactive decay?
Two radioactive materials A and B have decay constants 25λ and 16λ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of B to that of A will be "e" after a time `1/("a"lambda)` The value of a ______.
In the following atoms, which one is a radioisotope? Give one use of this isotope.
O16, C14, N14, He4
