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