How many watts are there in $1$ horsepower (in $watts$)?

State whether the following statement is true or false:
The rate of doing work is called power.

Define power. $A$ boy of mass $45 \, kg$ climbs up $20$ steps in $20 \, s$. If each step is $25 \, cm$ high,calculate the power of the boy used in climbing. (Take $g = 10 \, m s^{-2}$)

Define $1\, W$ of power. $A$ lamp consumes $1000\, J$ of electrical energy in $10\, s$. Calculate its power.

Calculate the electricity bill amount for the month of April if $4$ bulbs of $40 \, W$ for $5 \, hrs$, $4$ tube lights of $60 \, W$ for $5 \, hrs$, a $TV$ of $100 \, W$ for $6 \, hrs$, and a washing machine of $400 \, W$ for $3 \, hrs$ are used per day. The cost per unit is ₹ $1.80$.

Write the relation between the commercial unit of electricity and the $SI$ unit of energy.