Saved Bookmarks
| 1. |
For reduce in Ohmic loss transmission of electric power at very far distance of electric power is done at very high voltage ? |
|
Answer» Solution :`rArr` To reduce Ohmic loss transmission of electric power is done at very HIGH voltage. `rArr` Generally power station which produce electricity are very far from homes and factories. `rArr` Poweris transmitted by cables. `rArr` Length of cables is very large hence their resistance is also very large `[R alpha l ]` . Consider resistance of this cable be `R_(C)`. `rArr` Consider resistarnce a device be R. and voltage applied be V and current flowing through it is I then power, P = VI `rArr` Power DISSIPATED in cable be `P_(c)` then , `P_(c) = I^(2) R_(c) "" `....(1) But P = VI , then I = `(P)/(V)` `therefore P_(c) = (P^(2) R_(c))/(V^(2))"" ` [ From equation (1) ] `rArr` Thus , power dissipated is inversely proportional to `V^(2) ` hence to minimize this power `(P_(c))` voltage is transmitted at very high VALUE then power in cable will be reduced. `(V)/(I) = R_(eq) = R_(S) = `equivalent resistance `R_(S) = R_(1) + R_(2)` This can be extended for .n . NUMBER of resistors with different value. `R_(eq) = R_(S) = R_(1)) + R_(2) + .... + R_(n)` `therefore R_(eq) = sum_(i=1)^(n) `Ri `rArr` If .n. resistors of equal value (R) are connected in series, then equivalent resistance`R_(eq) = R_(S) = ` NR `rArr` Thus, in series connection of resistors equivalent resistance is larger than largest value of resistance. |
|