Modern Physics & Electronics
Albert Einstein was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics). He is best known for his mass-energy equivalence formula
E = mc2.
He received the 1921 Nobel Prize in Physics for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect, a pivotal step in the evolution of quantum theory.
Modern Physics & Electronics
Q. What is radioactivity?
Radioactivity is the emission or transmission of ions in the form of waves or particles through space or a material medium by the spontaneous disintegration of atomic nuclei. It is a Nucleic Phenomenon.
Three types of rays emitted from radioactive atoms-
Alpha - particle is a helium nucleus
Beta - electron which is a negative particle
Gamma-ray is electrically neutral
For example, we can say that the element carbon in whose nucleus there are six protons and its three isotopes are:
C12 : 6 protons and 6 neutrons
C13 : 6 protons and 7 neutrons
C14 : 6 protons and 8 neutrons
In 1896, Henry Becquerel discovered the existence of radioactive rays from Uranium for the first time. Later on, Ernest Rutherford, Pierre Curie, Marie Curie, and other scientists discovered the radioactivity of other elements. Since radioactivity is not influenced by external pressure, heat, electric or magnetic field, and cannot be controlled, it is accepted as a nuclear phenomenon. Due to radioactivity, radioactivity rays emerge and this changes the structure of the nucleus and turns it into a different element, this is also observed.
Uses of Radioactivity:
a) Medicine: To cure and determine tumor and cancer. Radioactivity is used to destroy harmful cells within the body. This is why, for the treatment of cancer radioactive elements are used to destroy cancer cells.
b) Agriculture: In the research of making advanced seeds.
c) Industry: To find out the number of different mineral substances, the radioactivity isotope of the following metal is used.
d) Zinc Sulfide is mixed with radioactive thorium and applied as a layer on the hands of clocks, which light up during the night.
e) Producing electricity: In nuclear plants, radioactivity is used to produce heat, which then produces a huge amount of electricity.
f) In 1885, Wilhelm Roentgen discovered a type of high-energy ray that can penetrate through muscles of the body and can create an image on a photographic plate. The nature of this ray was not known then and hence the ray was named X-ray.
CT Scan is the abbreviation of the word Computed Tomography Scan. Tomography means to create an image of a slice of a three-dimensional object. In medical science, X-ray is used in this machine. To make the image clear, often a special contrast material is injected into the patient's body.
a) Complete image of the soft tissues, blood carrying arteries and veins, lungs, brain etc. can be found by CT scan.
b) To diagnose cancer of the liver, lungs, and pancreas, CT scan is used.
c) CT scan can detect a tumor. It can also tell about the size and position of the tumor and how much affected the adjacent tissues.
d) Detect whether there is any problem in the blood circulation of the body.
MRI machine: The patient is kept in a very strong magnetic field and a radiofrequency electromagnetic wave is applied to his body. Analyzing the signals returning from the hydrogen protons inside the water molecules present in the body with a computer, the MRI machine makes images of the internal organs.