the sources of x rays and gamma rays respectively are

Cathode rays travel in straight lines from the cathode to anode and cast shadow of the object placed in their path. (a) Cathode rays travel in straight lines. Cathode rays consist of an invisible stream of negatively charged particles. When the plates X..

. Similarly, if the radiations given out by a radioactive substance are subjected to an electric field perpendicular to their path, they separate into three constituents. Those which turn towards the negative plate are the positively charged alpha particles. Those, which turn towards the positive p..

Beta rays are made up of streams of negatively charged particles similar to electrons. Thus, - particle has a unit negative charge and a negligible mass. They are electrons. Hence, - particle is represented as -1 e 0 . They affect photographic plate. They get deflected to the..

Above the troposphere is the stratosphere. This zone is rich in ozone. Hence, it is also called ozonosphere. In ozonosphere, oxygen in the presence of sunlight converts to ozone by photochemical dissolution. The ozonosphere completely absorbs short wave solar radiations, such as ultraviolet (uv) r..

A low-dose x-ray source moves in an arc (360 o ) around a specific part of the body being scanned and repeatedly sends out x-ray beams. As the beams pass through the body, the tissues absorb small amounts of radiation. Once the beam passes through, they are converted ..

> kilometers from the earth. Sun's light travels at a great speed of 3x10 5 kilometers per second, and takes about 8 minutes to reach us. Light takes about 4.3 years to reach us from the next nearest star called Alpha Centauri. The sun is a mass of hot gases, about 109 times bigger in siz..

>Three types of radiation from recognized radioactive elements are a -particles, b -particles and g -radiation. It was realized that radioactivity of an element is independent of its physical state, its chemical environment or temperature, suggesting that it is a property of the nucleus i.e., a nuc..

. It is abbreviated Z. Mass number is defined as the sum of the number of protons and neutrons in the nucleus of the atom. It is denoted by 'A'. Atoms of the same element having same atomic number but different mass numbers are called isotopes. Isotopes show similar chemical properties but the phys..

. This zone is called troposphere. Therefore, at higher altitudes, some of us find it difficult to breathe. Above the troposphere is the stratosphere. This zone is rich in ozone. Hence, it is also called ozonosphere. In ozonosphere, the sunlight converts oxygen to ozone by photochemical dissolution..

The mass of each β - particle is negligible. It has no mass. 4. Its velocity is less 10 7 cm/s. Its velocity is less than the velocity of light and is equal to 2.7 x 10 8 m/s Its velocity is the same as that of light and is equal to 3x10 8 m/s, 5. I..