Question

A metal wire of resistance 27 Ω is tripled on itself. Calculate the new resistance.

Answer 1

Answer:

When a wire tripled itself its length is 1/3 rd and area becomes tripled and area is inversely proportional to resistance.

case 1 :

R = p l/a                                                                    Here p = constant

27 ohm = p 30/a

a = 30/21 m²  

now length becomes 1/3 rd and area tripled

Therefore a = 30/27 * 3 = 100/9 m² and l = 1/3 * 30 = 10 m

Now R = p l/a

R = 100/9/10 = 1000/9 ohm