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The wries which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart ? Is the force attractive or repulsive? |
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Answer» Solution :It is given that `I_1 = I_2 = 300 A and d = 1.5 cm = 0.015 m`. Hence , the force per unit length between the wires is `F/l = (mu_0)/(4 pi) cdot (2 I_1 I_2)/(d) = (10^(-7) XX 2 xx300 xx 300)/(0.015) = 1.2 N m^(-1)` SINCE, the CURRENT in the wires are in mutually opposite direction, the force is REPULSIVE in nature. |
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