Question: When using a potentiometer to measure an unknown voltage, the balance point is found at 4 m. If the known voltage is 12 V, what is the unknown voltage?

Options:

1. 6 V
2. 8 V
3. 12 V
4. 16 V

Correct Answer: 12 V

Solution:

Using the formula Vx/Vk = Lx/Lk, we have Vx = Vk * (Lx/Lk). Here, Lx = 4 m, Lk = 10 m, Vk = 12 V, thus Vx = 12 V * (4/10) = 4.8 V.