ScientificIrfan

How to get 90% in board exam?🤘😇 Author: scientificirfan  * Current in a circuit is somewhat analogous to the flow of water in a closed system of pipes,with gravity playing the role of the electrostatic field,and a pump(motor) as a role of battery. In this sense, height is analogous to voltage. Most important and most repeated topics in BSEB/CBSE 12th  Physics: 1. Biot-Savart law 2. Young's double slit experiment 3. Lens maker formula 4. Gauss' law of electrostatics 4. PN junction and zener diode 5. Theory of microscope and telescope 6. Logic gate and truth table 7. Huygens' theory 8. Ampere's circuital law 9. Radioactivity 10. Mutual induction  and inductor 11. Wheatstone bridge 12. Potentiometer 13. Refraction at spherical surfaces 14. Electric dipole (potential and field) 15. Defects of vision and its corrections 16. Parallel plate capacitor 17. Bohr's model of the atom  18. Types of magnetic substances 19. Total internal reflection and rainbow 20. E

    Battery and EMF :-  What is battery?   What is EMF? Let's have some feeling of these two! A battery is a device which maintains a potential difference between its two terminals A and B.    Some " internal mechanism" exerts forces on the charges of the battery material (chemical of the battery). This force drives the postive charges of the battery towards A and the negative charges towards B. The force on a positive charge q is shown as Fb.   As positive charges accumulate on A and negative charges on B, a potential difference develops and grows between A and B. An electric field E is developed from A to B and exerts a force Fe= qE on a charge q.The direction of this force is opposite to that of Fb. In steady state, Fb=Fe and so no further accumulation of charge takes place. If a charge q is taken from the terminal B to A , the work done by the battery force Fb is W=Fb(d) where d is the distance between A and B. This work per unit charge is e= W/q = Fb(d)/q

      "Science is essential to life"  "The best thing about science is that whether you believe it or not  It doesn't matter "- N.D. Tyson Most often we are unaware of the importance of science that plays the most important role in our life. The fact is that it requires some basic knowledge and experience to know about this thing. Whether you know or not what science is, the most important thing is know how important science is in our life. The article you are reading right now, the picture you are seeing above, the phone you use,the house you live in,the medicine you get ,the AC you use,etc.  All these things became possible only because of science and it's the science that enabled us to see the invisible,to fly into sky and in space ,to see the distant stars and planets through the sophisticated and elegant inventions and discoveries of numerous instruments and techniques.  Then how can we forget and ignore the importance of science? And how ca

          Atmospheric Electricity: The earth's surface has a surface charge density of about 1nCm^-2.There is a corresponding electric field of about 100V/m in the atmosphere above the earth's surface (in the downward direction).So,the electric potential increases by about 100V as one move up by 1m.But the magnitude of the electric field gradually decreases as one move up. At about 50km above the earth's surface,the field is negligible.Thus, the potential difference between the earth's surface and the top of the atmosphere is about 400kV.  The atmosphere contains a large number of positive and negative ions. Their main sources are cosmic rays which come from the solar system and the interstellar bodies like stars and galaxies. The cosmic rays contains lots of protons,neutrons, electrons, neutrino and other particles and radiation as well. Dust particles also become charged due to friction when they move through the air. Because of the electric field in the a

Brownian Motion:  The  nature is full of beauty and elegance. From your daily life experiences, you are perhaps most familiar with 'motion'. The motion of your bicycle 🚲, the motion of the earth 🌎, the Sun,stars, galaxies, vehicles, aeroplane,etc. is the eternal part of nature that makes the universe exist. Everything is eternally in motion. A basic question that may arise in your mind is that what constitutes this eternal movement of these stuff in nature around us? That's what I have been fascinated to write this article!      Brownian Motion: In 19th century,there were enough experimental data to validate the kinetic theory of gases but the existence of atoms or molecules were still a mystery for physicists because there were no any direct experimental evidence for them. Most physicists thought that the molecules are alive and hence they have ability to move and perform various movements.But this idea had no any experimental support. In 1827,a botanist name

            Science General Knowledge 1. Does friction oppose motion? Ans: Friction only opposes relative motion. 2.Does earth move around the sun in circular orbit? Ans: Earth orbits around the sun in an elliptical orbit. 3. What is the most important part of the heart❤️?  Ans: Pacemaker. 4. When did Big Bang occur? Ans: About 13.8 billion years ago. 5. What happens in cancer? Ans: Cancer leads to uncontrolled growth of cells. 6. For what discovery was Einstein awarded the Nobel prize? Ans: Photoelectric effect  7. What are four types of waves? Ans: Matter wave, mechanical wave, electromagnetic wave and gravitational wave 8. Write seven em waves in order decreasing wavelengths. Ans: Radio wave, Microwave, infrared wave, visible light, ultraviolet wave, x-ray, gamma ray. 9. On what fact does the electron microscope depend on? Ans: Wave nature of electron. 10. What is the energy of a single photon? Ans: It is given by E=hf          where f is the frequency of the photon. 11. How man

The Discovery of Neutron: If the energetic alpha-particles emitted from Polonium fell on the light elements like berrylium,boron or lithium,a neutral radiation( radiation made of uncharged particles) was produced. Scientists thought that this new radiation could be gamma radiation but it was more powerfully penetrating than all known gamma radiations. When this radiation was passed through paraffin wax it ejected protons of very high energy (~5MeV). This observation was not in itself inconsistent with the assumed gramma ray nature of the new radiation but that interpretation of Compton scattering had a logical problem. From the energy and momentum conservation ,a gamma radiation would have to have impossibly very high energy to scatter high energy massive protons. Ettor Majorana declared that the manner in which the radiation interacted with protons required to be a new neutral particle. After hearing about these results, Chadwick performed a series of experiments showing that the gamm