Confused: potential difference vs. voltage drop?

[xxavenue]

Homework Statement

In Fig. 28-5a calculate the potential difference across R2, assuming = 14 V, R1 = 6.0 , R2 = 3.0 , and R3 = 2.0.

(image isn't working online, but it's a simple circuit- all the resistors are in series)

Homework Equations

V = IR

The Attempt at a Solution

Req = R1 + R2 + R3 = 11 ohms
I = V/Req = 14/11 = 1.27 A
V = IR1 = 1.27 * 6 = 7.62 V
V = IR2 = 1.27 * 3 = 3.81 V

So I know the voltage drop across R1 and R2, but I'm confused- what's the difference between calculated voltage drop and the potential difference across the resistor?

Many thanks.

 

[Dick]

I think 'voltage drop' and 'potential difference' mean exactly the same thing. You seem to be doing just fine.

 

[kerimek]

Potential difference and voltage drop are often used interchangeably, but there is a subtle difference between the two.

Voltage drop refers to the decrease in voltage that occurs across a component, such as a resistor, in a circuit. It is calculated using Ohm's law, V=IR, where V is the voltage drop, I is the current flowing through the component, and R is the resistance of the component.

On the other hand, potential difference refers to the difference in electric potential between two points in a circuit. In other words, it is the change in electric potential energy per unit charge as the charge moves from one point to another. In this case, the potential difference across R2 would be the difference in electric potential between the points before and after the resistor.

In the given circuit, the calculated voltage drop across R2 is 3.81 V, but the potential difference across R2 would be 7.62 V. This is because the potential difference takes into account the potential difference across all the components in the circuit, while the voltage drop only considers the specific component.

I hope this clarifies the difference between voltage drop and potential difference for you. It's important to understand the distinction between the two in order to accurately analyze and calculate values in a circuit.