Explanation:
The word BOOK; is made up of 4 letters and each actually represents the symbol of an element.
An element is a distinct substance that cannot be split-up into simpler substances.
B - Boron
O - Oxygen
O - Oxygen
K - Potassium
We can see that the word BOOK shows us elements boron, oxygen, oxygen and potassium.
D. Rock because it is not living
“Water” is the best thermal insulator.
Option: B
<u>Explanation</u>:
“Thermal insulators” are the materials which do not allow heat to transfer. “Water” is the substance which does not transfer heat. Hence, the “water” is the best “thermal insulator”. Water is the bad conductor of thermal heat. Water has “low thermal conductivity” than other substances, so this acts as an insulator as long as it is not traveled from one place to another. Heat is transferred when a “hot object collides” with “the cold objects”. The “thermal conductivity” of “water” is 0.6 W/m K.
The principle of radiation protection is to trigger deterministic and stochastic effect.
Explanation:
The main aim of principle of radiation is to prevent the deterministic effects of radiation and reduce the risks of stochastic effects.
There are three general principals of radiation used for dealing with ionising radiation are Justification, Dose limitation and Optimization.
The three basic radiation principles are time, distance and shielding.
The risk of exposure to radiation is measured using the conventional unit rem or SI unit (sievert).
H:O = 4:5;
(UO₂)₂ = 4 O atoms;
(PO₄)₂ = 8 O atoms:
8H₂O = 16 H atoms + 8 O atoms;
Total = 16 H atoms + 20 O atoms;
H:O = 16:20 = 4:5
