science for grade 1

Kilowatt and megawatt are higher units of power. Another unit of power is horse power 1 horse power = 746 wat..

2 on an object of mass 1 kg..

Calculate the momentum of a toy car of 150 g moving with a speed of 5 m/..

Natural chlorine consists of two isotopes: Calculate the average atomic mass of chlorin..

Question: The science of classification is called 1. demography 2. taxonomy 3. biology 4. none of the above Answer: ..

Question: Explain 'Dobereiner's Triads and its drawback. Answer: Dobereiner classified elements into groups of three where the atomic weight of the middle element was approximately the average of the atomic weights of the other two. Example: A triad of lithium (Atomic weight = 7), Sodiu..

Question: Which one of the following is an example of non-renewable resources? 1. Wind 2. Water 3. Vegetation 4. Coal and minerals Answer: ..

Question: Define a chemical change. Answer: A chemical change is a permanent, not easily reversible change in which the identity of the substance is altered to produce one or more new substance..

Question: The bending of a beam of light when it passes obliquely from one medium to another is known as _______. 1. reflection 2. refraction 3. dispersion 4. deviation Answer: ..

Question: Define the terms: Acid, alkali and salt. Answer: An acid is a compound, which releases hydronium ions (H 3 O + ) as the only positive ions in solution. An alkali is a compound, which releases hydroxyl ions (OH - ) as the only negative ions in solution. A salt is one o..