Electricity I - SS3 Physics Past Questions and Answers - page 1

Electric charge is a fundamental property of matter that arises from the presence or absence of electrons. Electric charge is measured in units of coulombs (C), and the charge on a single electron is -1.602 × 10-19 C. Charge can be positive, negative, or neutral. The positive charge is associated with the absence of electrons, while the negative charge is associated with the presence of extra electrons. Neutral objects have an equal number of positive and negative charges.

Electric current is the flow of electric charge through a conductor. It is measured in units of amperes (A), which is equivalent to coulombs per second. Voltage, also known as electric potential difference, is a measure of the potential energy difference between two points in an electric circuit. It is measured in units of volts (V). According to Ohm's law, the relationship between electric current, voltage, and resistance is given by the equation I = V÷R, where I is the current, V is the voltage, and R is the resistance of the circuit. This equation states that the current in a circuit is directly proportional to the voltage and inversely proportional to the resistance.