Question

a letter A is constructed of a uniform wire with resistance 1 ohm per cm. The sides of the letter are 20cm and the cross piece is 60degree. The resistance between the ends of the legs is close to?

Answer 1

first we need to calculate the length of each part of A.

for the starting we need to do some maths to calculate the center part of the A

lets consider A as a delta triangle then the base of the triangle is also 20c.m.

assuming the center line of A is at the middle of sides then the size of center line would be half of base that is 10cm.

from this we know traingle is as 60 degree so the upper trianlge would also be having same length. hence upper part of A is al 10cm.

thus the upper triangle of A makes 3 wires of 10cm hence having 10Ω.

the lower legs of the A are also 10cm each hence have 10Ω resistance each.

now use resistance in series and parallel to solve A.