Which of the following impacts the rate of heat developed in a resistor?

• A. Current and resistance
• B. Voltage and length
• C. Temperature and pressure
• D. Material and surface area

Answer: (A)

The rate of heat developed in a resistor is governed by the relationship stated in Joule's Law, which indicates that the power (or rate of heat) dissipated by a resistor is proportional to the square of the current passing through it and the resistance of the resistor. This can be mathematically represented as ( P = I^2R ), where ( P ) is the power (heat produced), ( I ) is the current, and ( R ) is the resistance.

Therefore, when the current increases, the heat developed increases significantly due to the square relationship. Similarly, higher resistance at a given current also leads to more heat being generated. Consequently, the combination of both current and resistance is essential in determining how much heat energy is produced in the resistor.

The other options relate to different physical phenomena or properties that do not directly affect the heat generation in the context of a resistor's electrical characteristics. For example, voltage is related to current and resistance via Ohm's Law but does not directly measure the heat output. Length and material can influence resistance but are secondary factors. Temperature and pressure can affect resistance and material properties but are not direct measures of heat generation in the resistor. Surface area is also relevant to heat dissipation rather