S block elements important question pdf || class 11 || S block ||

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Important Multiple Choice Questions of physics || Class 11 ||

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1. A particle moves along a straight-line y= 3x + 5. Which coordinate changes at faster rate? a) X- coordinate  b) y-coordinate  c) both x and y  d) insufficient data Ans: b) y-coordinate ( Let suppose x=1,then y=8 ,x= 2 ,y = 11. So y coordinate is increasing 3 times faster as compare to X- coordinate  ) .  2. If š“āƒ— + šµāƒ—āƒ— = š¶āƒ— and A+B = C then the angle between š“āƒ— and šµāƒ—āƒ— is- a) 0 b) Ļ€/4  c) Ļ€/2  d) Ļ€  Ans: c) Ļ€/2 3. If a unit vector is represented by 0.5š‘–āˆ’ 0.8š‘—+ c k then the value of ā€˜cā€™ is- a) 1  b) āˆš0.11  c) āˆš0.01 d) āˆš0.39 Ans: b) āˆš0.11 4. Given that A = B. what is the angle between (š“āƒ— + šµāƒ—āƒ—) and (š“āƒ— āˆ’ šµāƒ—āƒ—āƒ—āƒ—āƒ—āƒ—āƒ—āƒ—) =? a) 30Ā° b) 60Ā° c) 90Ā° d) 180Ā° Ans: d) 180Ā° 5. What is the component of the (3i+4j) along (i + j)? a) Ā½ (i + j)  b) 3/2(i + j)  c) 5/2 (i + j)  d) 7/2 (i + j) Ans: d) 7/2 (i + j) 6. What is the value of (š“āƒ— + šµāƒ—āƒ—).( š“āƒ— Ɨ šµāƒ—āƒ—)? a) 0  b) AĀ²-BĀ² c) AĀ²+BĀ²+2AB  d) None of these Ans...
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KVS CBSE Worksheets CHAPTER 1 Electric Charges and Fields Class 12

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                      SECTION A CONCEPTUAL AND APPLICATION TYPE QUESTIONS  1 Is the force acting between two point charges q1 and q2 kept at some distance apart in air attractive or repulsive when i) q1 q2 > 0 ii) q1 q2 < 0 ? 1 (2007)  2 If the distance between two equal point charges is doubled and their individual charges are also doubled ,what would happen to the force between them ? 1(2014)  3 Do the electrostatic field lines form closed loops? 1(2014)  4 A hollow metal sphere of radius 5cm is charged such that the potential on its is 10V. What is the electric field at the center of the sphere? 1(2011)  5 What is meant by the statement that   ā€œthe electric field of a point charge has spherical symmetry whereas electric field due to an electric dipole is cylindrically symmetricalā€™ā€™ ? 1(1996)  6 Why is it difficult to perform electrostatic experiments on a humid day? 1  7 The ...
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Distinction between Electromagnetic Waves and Matter Waves

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  Difference   between Electromagnetic Waves and Matter Waves Ā» Electromagnetic waves 1. Electromagnetic waves are associated with electric and magnetic fields perpendicular to each other and to the direction of propagation of radiation. 2. Electromagnetic waves can be radiated into space or emitted. 3. They do not require any medium for propagation i.e., these waves can pass through vacuum. 4. All electromagnetic waves travel with the same velocity.  5. The velocity of all electromagnetic waves is equal to that of light (3 x 108 m/s). 6. The wavelengths of electromagnetic radiation are much large .   Ā» Matter waves 1. Matter waves may not be associated with electric and magnetic fields. 2. Matter waves are neither radiated into space nor emitted by the particles. These are simply associated with the particles 3. They require medium for propagation i.e., these waves cannot pass through vacuum. 4. Matter waves travel with different vel...
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Occurrence of Metals || Process involved in formation of pure Metals || Getting the pure metals by different methods ||

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                Occurrence of Metals The earthā€™s crust is the major source of metals. It contains many variety of metals which are not know in the present days. Seawater also contains some soluble salts such as sodium chloride, magnesium chloride, etc. The elements or compounds, which occur naturally in the earthā€™s crust, are known as minerals. At some places, minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores.   1. Extraction of ores : We all know about the reactivity series of metals and we know Potassium(K) is the most reactive metal and Platinum(P t) is the least reactive. How a metal is extracted from its ore. Some metals are found in the earthā€™s crust in the free state and some are found in the combined state with other reactive metals like amalgam, ferrous sulphate, etc. Some are found in the form of their compounds. The metals ...
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