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Explain power produced in electrical circuit. |
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Answer» Solution :`rArr` In electrical cell, as long as chemical reaction takes PLACE it provide electrical power. `rArr` A simple schematic diagram for electric cell (electrochemical cell ) is shown in figure below.  `rArr` Two rod are kept in electrolyte. One rod act as positive electrode and second rod act as negative electrode. `rArr` When external resistor R is connected between positive and negative electrode power dissipated in R DEPEND on current (I) and potential difference (V), [ P = `I^(2) R ` and P = VI] `therefore Delta K = H` `therefore Delta W= IV Delta ` t`"" ` (from equation (2) ) from work energy theorem , `Delta K = Delta W = I Delta ` V ` therefore (Delta W)/(Delta t) = ` VI `(Delta W)/(Delta t) = `P = Power `therefore ` P = VI `rArr` Power: Energy dissipated PER unit time is callee power. From Ohm.s LAW, V = IR P = (IR) R = `I^(2) ` R P = V `((V)/(R)) = (V^(2))/(R) ` THUS, there are three equation of power p = VI, P = `I^(2) ` R and P= `(V^(2))/(R)` `rArr` J/s or watt is unit of power . `rArr` Ohmic loss : In a conductor energy gained by charges or energy Jost in form of heat energy is called Ohmic loss or energy loss. `rArr`In above equation power dissipated in resistor (R) depend on current passing through conductor and potential difference V between conductor. `rArr` Power transmitted at very large distance is at very high voltage then current flowing in them is also of very large value. Hence, high voltage danger sign is provided because electricity at such high voltage is not safe. |
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