A resistive heating element intended for industrial use is rated at when connected…
PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
A resistive heating element intended for industrial use is rated at 400W when connected directly to an 80V source.
An engineering team must operate this element from a 120V supply without exceeding its rated power. To accomplish this, they plan to add a single "ballast" resistor in series with the element.
(a) Determine the resistance of the heating element at its rated operating point.
(b) Calculate the resistance the ballast resistor must have so that the heating element still dissipates 400W when powered from the 120V supply.
(c) Once the ballast resistor is installed, determine the total current drawn from the 120V source.
(d) Compute the power dissipated in the ballast resistor itself and discuss one potential concern this presents for the physical design of the system (e.g., heat management or energy efficiency).