September 9, 2014

Points to Learn - Early Medieval India

(Indian History for UPSC Civil services Preparation, SSC , Bank Po & APPSC Exams)
  1. The Bhakti movement, in true sense, emerged from the south India when Alvar and Nayanar saints popularized the worship of Vishnu and Shiva respectively.
  2. The Ratha temple at Mahabalipuram was built by Narsimhavarman.
  3. The port city of Mahabalipuram of Mamallapuram was founded by Narsimhavarman.
  4. In post Gupta period we find the practice of worshipping Brahma, Ganapati, Vishnu, Shakti and Shiva which were collectively called Panchdeva or five divinities.
  5. The temples, having Panchdeva in its inner shrine, were called Panchayatana in post Gupta period.
  6. Hiuen Tsang has called the Shudras as agriculturists.
  7. Sushruta samhita is a work on medicine by Sushruta in which he describes the method of operating catraract, stone diseases and several other ailments.

August 20, 2014

Gamma Rays- Formation, Properties, Their difference with X Rays and Applications - Explained

Discovered by - Paul Villard, a French physicist,  is credited with discovering gamma rays. He had discovered they were emitted from radioactive substances and were not affected by electric or magnetic fields.Named as “Gamma rays” three years later by Ernest Rutherford.
-Gamma Rays - are electromagnetic rays like X rays and travel with speed of light. Electromagnetic radiation can be described in terms of a stream of photons, which are mass less particles each travelling in a wave-like pattern and moving at the speed of light. Each photon contains a certain amount (or bundle) of energy, and all electromagnetic radiation consists of these photons.
 -Gamma-ray photons have the highest energy in the EMR spectrum and their waves have the shortest wavelength. Their high frequency makes them more penetrating compared to X Rays.

August 17, 2014

X-Rays- Formation, Properties & Applications Explained

In 1895, Wilhelm Roentgen discovered X-rays. This accidental discovery took place when he was studying cathode rays using an evacuated glass tube. X-Rays are electromagnetic radiations having a wavelength between 10A to 0.01A. In Free Space they travel in a straight line with a velocity of 3 ×10 (power) 8 meters per second and they are Invisible to human Eye.

Formation: When cathode rays strike against a metal of high atomic weight, a new form of radiation called X-rays, are produced. X-rays are generated when a stream of electrons travelling from tungsten filament (cathode) is suddenly stopped by its impact on anodic tungsten target .

August 15, 2014

Liver - Anatomy, Functions, Diseases & Tests Explained

Why is liver called a Gland?
Gland is a organ which can secrete chemicals or hormones. In this case Liver produces bile, a substance needed to digest fats. Bile’s salts break up fat into smaller pieces so it can be absorbed more easily in the small intestine.
The liver is the largest glandular organ in the body. Liver is the only organ in the body that can regenerate itself in human body.
The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm, and on top of the stomach, right kidney, and intestines. Shaped like a cone, the liver is a dark reddish-brown organ that weighs about 3 pounds ( or 1.5 kgs average)
The liver consists of four lobes, they are - the left, right, caudate, and quadrate lobes.
i) The left and right lobes are the largest lobes and are separated by the falciform ligament. ii) The right lobe is about 5 to 6 times larger than the tapered left lobe.
iii) The small caudate lobe extends from the posterior side of the right lobe and wraps around the inferior vena cava.
iv) The small quadrate lobe is inferior to the caudate lobe and extends from the posterior side of the right lobe and wraps around the gallbladder.