diamond, a mineral composed of pure carbon. It is the hardest naturally occurring substance known; it is also the most popular gemstone. Because of their extreme hardness, diamonds have a number of important industrial applications. The hardness, brilliance, and sparkle of diamonds make them unsurpassed as gems. In the symbolism of gemstones, the diamond represents steadfast love and is the.

#2 JEE Advanced Joint Entrance Examination (Advanced) is the next on the list Top 20 toughest exams in India. This is designed to ensure that only candidates with very good IQ levels make an entry into prestigious institutions like IITs and IISCs to study engineering courses.

5. Nursing. Nursing is the hardest science major because students study science topics, including chemistry, psychology, anatomy, and physiology. Furthermore, the coursework is long and complex because it involves a lot of lab work, visiting hospitals, and working with patients.

Example 1: Find the value of all trigonometric ratios at angle A, if in any triangle ABC right angled at B AB=24, BC=7. Solution: For any right angled triangle using Pythagoras theorem we get AB 2 +BC 2 =AC 2 24 2 +7 2 = AC 2 and hence AC =25. Therefore from the figure Sin A = 7/25 Cosec A = 25/7 Cos A = 24/25 Sec A = 25/24

Diamond is the hardest natural substance in the world. This is due to its unique atomic structure of carbon atoms arranged in a lattice like pattern. This structure is highly resistant to any type of deformation, and therefore, it is also extremely difficult to scratch or break.