Question

One kilowatt is equal to ________ horsepower.
$A.1.34$
$B.1.36$
$C.10$
$D.746$

Answer 1

Hint: We will use the relation of conversion of watt into horsepower to get the correct answer. We know that $$1000W=1kW$$. We also know that the SI unit of power is watt. $1W$ power is defined as the ratio of $1J$ work to $1s$ time.
Formula Used: We are going to use the following two relations to solve this problem:- $$1000W=1kW$$ and $1hp=746W$.

Complete answer:
Power is defined as the rate of work done. Mathematically it is given as follows:-
$P={\displaystyle \frac{w}{t}}$
Where, $P$ denotes power, $w$ represents work done and $t$ is time interval.
SI unit of power is watt which is joule per second.
Power is a scalar quantity because it has only magnitude.
We also know that
 $1kW=1000W$……………… $(i)$
We also have
$1hp=746W$………………… $(ii)$
Where $hp$ represents horsepower.
From equations $(i)$ and $(ii)$ we get
$1kW={\displaystyle \frac{1000}{746}}hp$

Therefore option $(A)$ is correct.

Additional Information:
We should know the fundamentals of the horsepower unit. Horsepower is a unit of measurement of power. It is generally used to measure the power of engines. Horsepower is a unit in English system or foot-pound-seconds (fps) . Horsepower is defined as $550$ foot pound per second. It is used to measure the high magnitudes of power of an engine. It was used after the development of steam engines because the output of an engine can be compared to the power of the horse.

Note:
Units of power should be carefully used. We should not get confused over the fact that $1hp=746W$and not $1hp=1kW$. We should also take care of the fact that the SI unit of power is watt and not horsepower. Horsepower is a unit in English system. It is used to measure high magnitudes of power produced by engines and motors.