Question

When 7/0.029 V.I.R cable is carrying 20 A, a drop of 1 V occurs every 12 m. The voltage drop in a 100 m run of this cable when it is carrying 10 A is nearly
1. 4.2 V
2. 3.2 V
3. 1.2 V
4. 0.42 V

Answer 1

Correct Answer - Option 1 : 4.2 V

If a cable is carrying 20 A current, then the voltage drop is 1 V for 12 m.

If a cable is carrying 10 A current, then the voltage drop is 0.5 V for 12 m.

The voltage drop for 100 m is \( = \frac{{100}}{{12}} \times 0.5 = 4.2\;V\)