Question

How many watts equal $1$ horsepower?

• A. $746$
• B. $500$
• C. $646$
• D. $700$

Answer 1

The correct option is A

$746$

Power and its units

1. Power is defined as the amount of work done per unit of time.
2. If $P$ is the power, $W$ is the work done and $t$ is the total time taken, then, $P=\frac{W}{t}$
3. The unit of work done is joules or $J$ and the unit of time is seconds or $s$.
4. Therefore, the derived unit of power is $J/s$.
5. This is also expressed as Watt or $W$ which is the SI unit of power.

Value of horsepower

1. Horsepower is another unit of power.
2. It is generally used to express the power of engines.
3. One horsepower is defined as the power required to move an object of $550$ pounds through a displacement of $1$ foot in $1$ second.

$\therefore 1$ horsepower$=746W$

Hence, the correct answer is option (A).