Trigonometric Angles Trigonometric angles are very easy to learn if u follow some of these steps- From the table ,just learn the values of sin θ upto 90 and now see that as now move from left to write in sin θ ,the same values will come when you move from right to left in cos θ .Now the next column is of tan θ ,we know that tan θ =sin θ /cos θ ,so we can easy calculate by dividing sin θ and cos θ .Then next we move on to cot θ ,which can be find out by doing inverse of tan θ or by dividing cos θ and sin θ ,as cot θ =1/tan θ or cot θ =cos θ /sin θ .now go to sec θ ,it is reciprocal of cos θ ,cos θ =1/cos θ ,and at the end it is cosec θ ,which can be find out by finding reciprocal of sin's value,as cosec θ =1/sin θ . Angles can be c omplementary angles and complex angles
CARBON AND ITS COMPOUND(1-5) Question-1 Why does graphite conducts electricity, but not diamond? Solution: In case of diamond, each carbon atom of a single crystal is surrounded by four other carbon atoms by covalent bonds such that they form four corners of a regular tetrahedron. Because of four covalent bonds with each carbon atoms there are no free electrons available. Due to the non-availability of free electrons within crystalline structure, diamond acts as a bad conductor of electricity. In case of graphite, every carbon atom in a single crystal is covalently bonded to three carbon atoms. As each carbon atoms has four valence electrons one valence electron is left free for each carbon atom. These free electrons can be easily made to flow within the crystalline structure of graphite by applying electric potential. Thus, graphite is a good conductor of electricity. Question-2 Write three important uses of ethanol...
PERIODIC CLASSIFICATION OF ELEMENTS(8-13) Question 8: Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice? Answer: Calcium (Ca) and strontium (Sr) are expected to show chemical reactions similar to magnesium (Mg). This is because the number of valence electrons (2) is same in all these three elements. And since chemical properties are due to valence electrons, they show same chemical reactions. Question 9: Name (a) three elements that have a single electron in their outermost shells. (b) two elements that have two electrons in their outermost shells. (c) three elements with filled outermost shells. Answer: (a) Lithium (Li), sodium (Na), and potassium (K) have a single electron in their outermost shells. (b) Magnesium (Mg) and calcium (Ca) have two electrons in their outermost shells. (c) Neon (Ne), argon (Ar), and xenon (Xe) have filled outermost shells....
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