Physics · Electrostatic Potential

If an arbitrary constant \( \alpha \) is added to the electrostatic potential energy at every point in space, what will happen to the potential energy difference \( \Delta U = U_P - U_R \) between two points P and R?

1. It increases by \( 2\alpha \)
2. It increases by \( \alpha \)
3. It decreases by \( \alpha \)
4. It remains unchanged