# Why is the voltage across resistors on an experiment slightly different from the calculations?

The voltage across resistors in an experiment may differ slightly from calculated values due to several factors. One reason is the tolerance of the resistors used in the experiment. Resistors have a specified tolerance that indicates the allowable deviation from their nominal resistance value. If the resistors used have a tolerance of, for example, ±5%, the actual resistance values could vary slightly from the values assumed in calculations, leading to corresponding variations in the voltage drop across them. Additionally, factors such as temperature variations, slight inaccuracies in measurement equipment, or parasitic resistances in the circuit (like contact resistances) can contribute to discrepancies between calculated and measured voltages.

Measured voltage across resistors can differ from calculated values due to practical considerations and real-world conditions. Calculated voltages are based on ideal assumptions such as perfectly accurate component values and ideal circuit conditions. In practice, resistors may have tolerances that result in actual resistance values deviating slightly from their nominal values. Other factors such as the presence of parasitic resistances, imperfect connections, or variations in power supply voltage can also contribute to differences between measured and calculated voltages. Measurement errors or limitations of the measuring instruments can further impact the accuracy of voltage readings in experiments.

Differences between calculated and measured resistance values can stem from various sources. Calculated resistance values are typically based on ideal conditions and assumptions about the resistors’ specifications and circuit configuration. In contrast, measured resistance values take into account real-world factors such as the actual tolerance of the resistors, temperature effects, and the accuracy of measurement equipment. Tolerances in resistor values can lead to small variations between the intended and actual resistance values, which are reflected in measurements. Additionally, factors like aging of components or environmental conditions can affect the measured resistance values over time.

Resistors in series have different voltages across them because the voltage drop across each resistor depends on its individual resistance value and the current flowing through the series circuit. In a series circuit, the total voltage provided by the power source is divided among the resistors based on Ohm’s Law (V = IR), where V is voltage, I is current, and R is resistance. Since each resistor in a series circuit carries the same current, the voltage drop across each resistor is proportional to its resistance value. Therefore, resistors with different resistance values will have different voltage drops across them, reflecting their role in dividing the total circuit voltage.

Voltage changes across a resistor due to the relationship defined by Ohm’s Law, which states that the voltage drop across a resistor is proportional to the current passing through it and the resistance value itself. When current flows through a resistor, it encounters resistance, causing a voltage drop proportional to the current and the resistor’s resistance. This voltage drop represents the energy converted into heat as current passes through the resistor. Therefore, as the current through a resistor changes, the voltage drop across it also changes proportionally. This fundamental relationship explains why voltage changes across a resistor based on variations in current or resistance values in a circuit.