Final answer:
The rate of thermal energy generated in a 30-Ω resistor requires knowledge of the current through it and is calculated using the formula P = I2R.
Step-by-step explanation:
To calculate the rate at which thermal energy is generated in the 30-Ω resistor, we can use the formula P = I2R, where P is the power (rate of energy generation), I is the current, and R is the resistance. Since the current through the resistor is not given in the question, we do not have enough information to calculate the exact rate. However, if the current was given or could be determined from the context of the circuit in which the resistor is placed, the student could use this formula to find out the rate at which the resistor is generating thermal energy.