CBSE Class 10th Science | Chapter 5. Periodic Classification of Elements | Solved Exercises

Things to remember :

• From only 30 elements known around year 1800, today we have list of 114 known elements
• Elements are classified on the basis of similarities in their properties.
• Döbereiner grouped the elements into triads and Newlands gave the Law of Octaves.
• Mendeléev arranged the elements in increasing order of their atomic masses and according to their chemical properties.

Chapter 2. Principles Of Management | Business Studies | CBSE Class XII (12th) | Questions & Answers

CONCEPT MAPPING

• Concept: Principles of management are general guidelines which can be used under certain situations.
• Nature:
  1. Universal applicability
  2. Formed by practice
  3. Flexible
  4. Mainly behavioural
  5. Cause and effect relationships
  6. general guidelines contingent
  
  

CBSE Class IX (9th) Science | Chapter 10. GRAVITATION | Solved Exercises

Question 1.How does the force of gravitation between two objects change when the distance between them is reduced to half 


Answer. According to the law of gravitation , the force of attraction between any two objects of mass m1 and m2 is proportional to the product of their masses and inversely proportional to the square of the distance 'R' between them.

As given here	F =	Gm1 × m2
		R²