I WANT PHYSICS

 OHM’S LAW Before going to Ohm’s law let us discuss in brief about some electrical components or devices we use in electric circuits.    A Battery serves as a source of electricity in a circuit. We use mainly two measuring devices in this concept those are  Volt meter: used to measure potential difference between the two ends of a conductor. So it is always connected in parallel ( we learn about types of connections later in this chapter) Ammeter: used to measure the current passing in the circuit. So it is always connected in series. Now let us dive in to the activity did by Ohm to understand his concept. Materials required: 5 dry cells of 1.5V each, conducting wires, an ammeter, a volt meter, thin iron spoke of length 10cm, LED and key.   Procedure: Connect a circuit as shown in the above figure. Solder the conducting wires to the ends of the iron spoke. Close the key. Note the readings of current from ammeter and potential difference from volt meter in table     Now connect two cell

  WORKING OF BATTERY: A battery consists of two metal plates (electrodes) and a chemical (electrolyte). The electrolyte (chemical) between the two metal plates consists of positive and negative ions which move in opposite directions The electrolyte exerts a certain force on these ions and makes them move in a specified direction. Let us call this force as a chemical force (Fc). Depending upon the nature of the chemical, positive ions move towards one of the plates and accumulate on that plate.   As a result of this accumulation of charges on this plate it becomes positively charged (called anode). Negative ions move in a direction opposite to the motion of positive ions and accumulate on the other plate. As a result of this the plate becomes negatively charged (called cathode). This accumulation of different charges on respective plates continues till both plates are sufficiently charged.          But the ions in motion experience another force , when sufficient number of charges are a

  POTENTIAL DIFFERENCE: When the ends of a conducting wire are connected to the terminals of a battery, an electric field is setup throughout the conductor. This field exerts a force on the charge (electron). Let Fe be the force exerted by the electric field on a free charge q. The free charges accelerate in the direction of the electric field (If the free charges are electrons, then the direction of electric force on them is opposite to the direction of electric field). It means the electric field does some work to move free charges in a specified direction.                                Let the electric force made the charges move through a distance ‘l’ from A to B as shown in figure . We know that, the work is the product of force and distance along the direction of force. Hence, work done by the electric force on a free charge q is given by W = Fe l   [since work is the product of force and displacement] Work done by the electric force on unit charge = W/q = Fe l/q “Work done by t