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Grade 10Electric Current

The letter A is constructed of a uniform wire of resistance 3 ohm per centimetre the sides of the letter are 20cm and the cross piece in the middle is 10 cm long the resistance between the ends of the legs will be ??

Profile image of Timeslayer
6 Years agoGrade 10
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1 Answer

Profile image of Arun
6 Years ago
SInce the angle subtended is 60 degrees at the apex and both the sides are equal in length, the top of the letter A will make an equilateral triangle. hence all the three sides will be 10 3 cm each and correspondingly will have a resistance of 3 ohms each.The top triangle in A can be considered as 2 resistors of 3 ohms in series and 1 resistor of 3 ohm in parallel. Effective resistance of this traingle becomes 6/3 = 2 ohms. Now the effective circuit is 3 resistors of 3, 2 and 3 in series. Hence effective resistance is 8 = 8 ohms