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A room is lighted by `200W,124 V` incandescent lamps fed by a generator whose output voltage is `130 V`. The conducting wires from the generator to the user are made of aluminimum wire of total length 150 m and cross-sectional area `15 mm^(2)`. How many such length can be installed ? What is the total power consumed by the user ? sp. resistance of aluminium is `2.9 xx 10^(-4) Omega m ` |
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Answer» Correct Answer - `12,2.4kW` Resistance of aluminium wire `R_(Al) = (rho l)/(A) = (2.9 xx 10^(-8) xx 150)/( 15 xx 10^(-6)) = 0.29 Omega` current through main line `I = (130 - 124)/(0.29)= (20.69 )A` Current through one lamp `l_(1) = (200)/(124) = 1.613 A` ltb rgt No of lamps `= (20.69)/(1.613) = 12.83 = 12.85` Hence no of lamp to be used `= 12` power connected `= 12 xx 200 = 2400 W= 2.4kW` |
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