Question 907585
For a resistor in a direct circuit that does not vary its resistance, the power that a resistor must dissipate is directly proportional to the square of the voltage across the resistor.
The resistor must dissipate 1/16 watt power when the voltage across the resistor is 14 volts.
Find the power the resistor must dissipate when the voltage across it is 42 volts.
:
The power equation for this problem
P = {{{E^2/R}}} where E = the voltage, R = resistance in ohms, P in watts
Find the resistance
{{{1/16}}} = {{{14^2/R}}}
{{{1/16}}}R  = 196
multiply both sides by 16
R = 3136 ohms
:
When voltage is 42 volts
P = {{{42^2/3136}}}
P = {{{1764/33136}}}
P = .5625 watts ({{{9/16}}}) Watts
:
:
We can note here that when you triple the voltage, you increase the power by 3^2