Megajoule - Wattage

75 watts

A small lightbulb uses 1 megajoule of energy in a day. What is the wattage of the light bulb?

The megajoule (MJ) is equal to one million ($10^6$) joules

One day is equal to $24\times 60 \times 60 \ \text{seconds} = 86400 \ s$

Joules to watts calculation:
The power P in watts (W) is equal to the energy E in joules (J),
divided by the time period t in seconds (s):

$\begin{array}{|rcll|} \hline P(W) &=& \frac{E(J)}{ t(s) } \\ P(W) &=& \frac{10^6\ \text{J}}{ 86400\ \text{s} } \\ P(W) &=& \frac{1000000\ \text{J}}{ 86400\ \text{s} } \\ P(W) &=& \frac{10000}{864}\frac{\text{J}} {\text{s} } \\ P(W) &=& 11.5740740741\frac{\text{J}} {\text{s} } \\ P(W) &=& 11.5740740741\ \text{W}\\ \hline \end{array}$