Question

Which uses more energy, a $250\mathrm{W}$ TV set in $1\mathrm{hr}$, or a $1200\mathrm{W}$ toaster in $10\mathrm{minutes}$?

Answer 1

Step 1: Given information

In TV,

Power, $\mathrm{P}=250\mathrm{W}$

Time, $$\begin{gathered} \mathrm{T}=1\mathrm{hour} \\ =60\times 60 \\ =3600\mathrm{s} \end{gathered}$$

In toaster,

Power, $\mathrm{P}=1200\mathrm{W}$

Time, $$\begin{gathered} \mathrm{T}=10\mathrm{minutes} \\ =10\times 60 \\ =600\mathrm{s} \end{gathered}$$

Step 2: To find

Which uses more energy, than a TV or a toaster.

By using the formula, $\mathrm{E}=\mathrm{Pt}$ we can find the energy consumed by TV and toaster.

Step 3: Energy consumed by TV

By substituting the values in the above formula,

$$\begin{gathered} {\mathrm{E}}_1=250\times 1 \\ =250\mathrm{W}\mathrm{hr} \end{gathered}$$

Step 4: Energy consumed by toaster

$$\begin{gathered} {\mathrm{E}}_2=1200\times \frac{10}{60} \\ =200\mathrm{W}\mathrm{hr} \end{gathered}$$

Therefore, the TV uses more energy.