Question

Why does a galvanometer show momentary deflection?

Answer 1

Answer:

So in your case, the deflection is momentary because the capacitor draws some current during charging and during discharging it sources current.

Answer 2

Answer:

Galvanometer shows a momentary deflection when current is passed through it , we can see a sudden deflection and when key is open we still can see a deflection but in the opposite direction