this can be solve using the formula P = I^2 * Rwhere P is the powerI is the CurrentR is the resistanceP = I^2 * R
1/4 Watt = I^2 * 100 ohm solve for II^2 = 1/400 I = 0.05 amps then using the formula to solve for the voltage:V = I * RV = 0.05 amps * 100 ohms V = 5 volts