Correct option is A
Electric current (a): Electric current is defined as the rate of flow of electric charge through a conductor.
Mathematically, it is expressed as I=dQ/dt where I is the electric current, dQ is the change in charge, and dt is the change in time.
This definition directly corresponds to "changes in charge with respect to time."
Electric voltage (b): Electric voltage, also known as electric potential difference, is the energy per unit charge required to move a charge between two points. It is not directly related to the rate of change of charge.
Charge density (c): Charge density refers to the amount of electric charge per unit volume (volumetric charge density), per unit area (surface charge density), or per unit length (linear charge density). It describes how charge is distributed in space, not the rate of change of charge.
Electric static field (d): An electric static field is a field around charged particles that exerts force on other charges within the field. It is associated with stationary charges and does not directly describe the change of charge with respect to time.
Therefore, the correct answer is (a) Electric current.
