A uniform wire of resistance 10 is stretched such that its length becomes 3 times its original length. The stretched wire is then cut into 3 equal pieces, and these pieces are connected in parallel. The equivalent resistance of this combination is:

Step-by-step solution

When a wire is stretched to n times its original length, its volume remains constant. The new resistance becomes n^2 times the original resistance. Given n = 3 , the resistance of the stretched wire is: R_ stretched = 3^2 10 = 90 The stretched wire is then cut into 3 equal pieces. The resistance of each piece is: R_ piece = 90 3 = 30 When these 3 pieces are connected in parallel, the equivalent resistance R_ eq is: R_ eq = R_ piece 3 = 30 3 = 10 Answer: 10