Which uses more energy: a 250W TV set in 1 hour or a 1200W to aster in 10 minutes?
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Case1: TV set
P = 250W = 0.25 KWh
t = 1h
Energy consumed = P × t = 0.25 × 1 = 0.25KWh
Case2: Toaster
P = 1200W = 1.2KW, t = 10min $=\frac{10}{60}=\frac{1}{6}\text{h}$
Energy consumed $=\text{P}\times\text{t}=1.2\times\big(\frac{1}{6}\big)=0.2\text{kWh}$
Thus, TV uses energy.
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