Could someone please tell me why there is both a positive and negative sign with the systematic error? I thought it could only be either positive or negative. A student uses a digital ammeter to measure a current. The reading of the ammeter is found to fluctuate between 1.98A and 2.02A. The manuf...

What is it about a capacitor which allows it to filter frequencies? I understand the construction of a high pass RC filter, and the maths behind it, but I'm struggling to find an explanation of the physics behind the phenomenon. In my mind I can picture the broad spectrum signal hitting the capac...

The Wikipedia article for complete set of commuting observables (CSCO) outlines a method for finding a CSCO. However, it does not suggest why such a set should exist. On one hand, I think it is very possible that it might not in general, as most systems are not integrable. But on the other hand, ...

When an Electron Capture occurs a Neutron and a Neutrino are formed. Prior to this process due to the presence of the proton and electron an electric field must've existed however as soon as this process happens which is almost instantaneous i believe the electric field must vanish right? So what...

From a mathematical standpoint ( CPT symmetry ) it is most probable that anti-hydrogen has the same spectra ( absorption, emission ) than hydrogen. Within this hypothesis, how can we state that a far ( in a neighbor galaxy ) cloud or star is made either of hydrogen or anti-hydrogen?

When 2 positive charges are kept close, they get repelled in the direction of line joining both the charges. Why is it so? Also why the repulsion is in a straight path? In both the cases potential energy of charge which gets repelled decreases. What makes it repel in a straight line such that th...