Final answer:
The formula 1/Req = 1/R1 + 1/R2 + 1/R3 represents the total resistance in a parallel circuit. Electric current splits across the resistors in a parallel circuit, leading to this formula following Ohm's Law (I=V/R). This makes the equivalent resistance in a parallel connection determined by this formula.
Step-by-step explanation:
The equation 1/Req = 1/R1 + 1/R2 + 1/R3 represents the total resistance in a parallel circuit. In a parallel connection or circuit, resistors are arranged in separate branches, and the voltage remains constant across them all. The overall or equivalent resistance (Req) can be determined using this formula.
To prove it, consider the input of electric current 'I' in the circuit. The electric current splits across the resistors, so the total current 'I' in the circuit equals the sum of the currents across each resistor. So, I=I1+I2+I3. Using Ohm's Law (I=V/R), we get V/Req = V/R1 + V/R2 + V/R3. As 'V' is constant, canceling it gives the proven formula 1/Req = 1/R1 + 1/R2 + 1/R3.
Learn more about Parallel resistance