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Millikan's Oil-drop Experiment

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            Millikan's Oil-drop Experiment In 1909, Robert Millikan was the first to find the charge of an electron his now-famous oil-drop experiment. In that experiment, tiny oil drops were sprayed into a uniform electric field between a horizontal pair of oppositely charged plates. The drops were observed with a magnifying eyepiece, and the electric field was adjusted so that the upward force on some negatively charged oil drops was just sufficient to balance the downward force of gravity. That is, when suspended, upward force qe just equaled Mg. Millikan accurately measured the charges on many oil drops and found the values to be whole number multiples of 1.6 x 10-19 C the charge of the electron. For this, he won the Nobel prize.
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A charged particle is free to move in an electric field. It will travel (a) always along a line of force (b) along a line of force, if its initial velocity is zero (c) along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force (d) none of these.

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Ques :  A charged particle is free to move in an electric field. It will travel (a) always along a line of force (b) along a line of force, if its initial velocity is zero  (c) along a line of force, if it has some initial velocity in the direction of an acute angle with the line of force (d) none of these. Ans : (b) along a line of force, if its initial velocity is zero 
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An electron moving with a constant velocity v along X-axis enters a uniform electric field Y-axis. Then the electron moves (a) with uniform acceleration along Y-axis (b) without any acceleration along Y-axis (c) in a trajectory represented as y = ax² applied along (d) in a trajectory represented as y= ax

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Ques : An electron moving with a constant velocity v along X-axis enters a uniform electric field Y-axis. Then the electron moves  (a) with uniform acceleration along Y-axis  (b) without any acceleration along Y-axis (c) in a trajectory represented as y = ax² applied along (d) in a trajectory represented as y= ax Ans:  (c) in a trajectory represented as y = ax² applied along
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OHM’S LAW AND RESISTANCE

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            OHM’S LAW AND RESISTANCE Ohm’s Law : If the physical state i.e. temperature, nature of material and dimensions of a conductor remain unchanged then the ratio of potential difference applied across its ends to current flowing through it remains constant.                             V = I R R = V / I = resistance of conductor Resistance : SI Unit : volt/ampere or ohm () Conductance(G) : The reciprocal of resistance is called conductance.                              G = 1/ R SI Unit : ohm–1 or mho or siemens Dimensions : [M–1 L–2 T3 A2] The substances which obey ohm’s law are called ohmic or linear conductor. The resistance of such conductors is independent of magnitude and polarity of applied potential difference. Here the graph between I and V is a straight line passing through the origin. » The reciprocal of slope of straight line gives resistance.  » The substances which do not obey ohm’s law are called non ohmic or non linear conductors. » The I–V curve is not a stra
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Maxima and Minima || Local maxima || Local minima || Turning Point || Ist Order derivative test || IInd Order derivative test || Global Maxima and Global Minima || Class 12 Maths || AOD Application of derivative ||

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Current electricity important points copy notes Class 12 Chapter 3 Physics

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10th NCERT physics all SI units

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 Mass  → kilogram (kg)  Time → second (sec)  Speed → m/s Velocity → m/s Temperature → kelvin (K)  Amount of substance → mole(mol)  Length → meter (m)  Current (I) → Amphere (A)  Potential difference → volt (V)  Weight → kilogram (kg)  Luminous intensity → Candella (Cd) 
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Diagonal Relationship between Beryllium and Aluminium || Relation between Beryllium and Aluminium

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  Diagonal Relationship between Beryllium and Aluminium The ionic radius of Beryllium (Be 2+) is estimated to be nearly 31 pm; the charge/radius ratio Or e/m ratio is nearly the same as that of the Al 3+ ion. Hence beryllium resembles aluminium in these ways. Some of the similarities are given below: » Like Aluminium, Beryllium(be) is not readily attacked by acids H+ donor because of the formation of an oxide film on the surface of the metal by reacting with oxygen, i.e. they are rendered passive by nitric acid. » Beryllium hydroxide[[Be(OH)4]2] dissolves in excess of alkali to give a beryllate ion, [ Be(OH)4]2– just as aluminium hydroxide[Al(OH)3] gives aluminate ion, [Al(OH)4] » The chlorides of metals beryllium and aluminium have Cl– bridged chloride structure in vapour phase. Both the chlorides are soluble in organic solvents and are strong as Lewis acids They are used as Friedel Craft catalysts. » Beryllium(Be) and aluminium(Al) ions have strong tendency to form complexes, (BeF4)2
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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   “the electric field of a point charge has spherical symmetry whereas electric field due to an electric dipole is cylindrically symmetrical’’ ? 1(1996)  6 Why is it difficult to perform electrostatic experiments on a humid day? 1  7 The distance of the field point on the equatorial plane of a small electric dipole , is halved. By wha
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S-Block Elements || S-block element class 11 chapter 8 || Group 1A, 2A elements || S block elements chapter 8 notes class 11 || Chemistry ||

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                    INTRODUCTION : The s- block elements of the periodic table are those in which the last electron enters  into the outermost s-orbital. As the s-orbital can accommodate only two electrons, in two group (1 & 2) belong to the s-block of the periodic table. Group 1 of the periodic table consists of the elements : lithium (L i), sodium (Na), potassium (K), rubidium (R b), caesium (C s) and francium (F r). They are collectively known as alkali metals. These are called because they forms hydroxides on reaction with water which are strongly alkaline in nature. The elements of Group 2nd include beryllium (Be), magnesium (Mg), calcium (C a), strontium (S r), barium (B a) and radium (Ra). These elements with the exception of Beryllium are commonly known as the alkaline earth metals. These are so called because their oxide and hydroxide are alkaline in nature and these metal oxides are found in the earth’s crust . The general electronic configuration of s- block element is
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Kinematics Important Questions Of Physics

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Ques 1. Mention the condition when an object is in motion (a) can be considered point object (b) can not be considered point object.  Ans . An object can be considered as a point object if (a) its size is negligible in comparison to the distance travelled by object (b) it's size is not negligible in comparison to the distance travelled by object. Ques 2 . Can Earth be regarded as a point object when it is describing its really journey around the sun? Ans.  Yes, because the diameter of earth is very small as compared to the radius of the orbital path of earth around the sun.   Ques 3. Can the speed of a body be negative?   Ans . No, because the speed of an object is the distance travelled by the by object in unit time and distance can never be negative. Ques 4. which speed is measured by the speedometer of your scooter?  Ans . The Speedometer measure the instantaneous speed of the scooter at a given instant of time. Ques 5.What does the slope of position time 
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QUANTUM NUMBERS (Principal, Azimuthal, Magnetic and Spin)

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                  QUANTUM NUMBERS  Orbitals represent regions in the space around the nucleus where the probability of finding the electron is maximum. A large number of electron orbitals are possible in atom. These can be distinguished by their size, shape and orientation of the orbitals. To describe each electron in an atom in different orbitals, we need a set of three numbers known as quantum numbers. These are designated as n, l and m. In addition to these three numbers another quantum number is also needed which specifies the spin of the electron. These four numbers are called quantum numbers. These are discussed below: 1. Principal quantum number (n) :  This quantum number determines the main energy shell or level in which the electron is present. It is denoted by n. It can have whole number values starting from 1 such as n = 1, 2, 3, 4 ... This quantum number also identifies as shell. The shell with n 1 is called the first shell. The shell with n 2 is called the second shell and
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