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PhysicsElectricity
Joule's Heating Effect
Explore H = I²Rt and understand why fuse wires melt.
Controls
2 A
20 Ω
60 s
Live result
Heat H = I²Rt
4800J
Power
80W
Heat (J)4800
Joule heating — H = I²Rt4,800 J
Power = I²R = 80 W · 60sVery hot
Real-time graph — power & heat vs time
t = 0.0 sH = 0 J
Power stays constant (blue dashed) while heat piles up in a straight line — H = P × t. Raise the current and the blue line jumps by I², so the orange heat line climbs far steeper.
Electrons collide with the metal ions and lose energy as heat. Double the current and the wire gets 4× hotter — that's why a thin fuse wire melts first and breaks the circuit.
Heat depends on the square of current — doubling current gives 4× the heat.