The resistance of a piece of a wire is 15Ω. It is bent to form an equilateral triangle. What is the equivalent resistance between any two corners of the triangle?

1. 3.3 Ω
2. 5 Ω
3. 10 Ω
4. 15 Ω

The resistance of a piece of a wire is 15Ω. It is bent to form an equilateral triangle. What is the equivalent resistance between any two corners of the triangle?

The resistance of a piece of a wire is 15Ω. It is bent to form an equilateral triangle. The equivalent resistance between any two corners of the triangle is 3.3 Ω.

1. using shortcut
2. when you have an equilateral triangle means a triangle having equal sides, and you want to find the equivalent resistance between any two corners of the triangle then used this formula
3. equivalent resistance: Req = 2/3 * r
4. where r is the resistance of any resistor.
5. put r = 5 in our case get 2/3 * 5 = 10/3 = 3.3 Ω
6. using another method to find equivalent resistance
7. from the figure, any two resistors are in series and equivalent resistance for these two resistors are
8. Req = 5Ω + 5Ω = 10Ω
9. this equivalent resistance in parallel with the third resistor
10. 1/Req = 1/10 + 1/5 = 3/10
11. hence Req = 10/3 = 3.3Ω

This question is about MSc Electricity and Magnetism MCQs. This is the previous year’s question about the competitive exams.