Question

Practical unit of power are

• A. KW
• B. MW
• C. GW
• D. $hp$

Answer 1

Answer: (A), (D)

$hp$

Practical unit

The practical unit of an electrical instrument is the unit that is used in practical applications to measure magnitudes. As a result, this device should be utilized on a regular basis.

The explanation of the correct option

In case of option A

1. The rate of energy per unit time is already measured in power units like $kW$ ($kW=kJ/s$).
2. Kilowatt-hours are the product of power and time, not the rate at which power changes over time. Watts per hour $(W/h)$ is a metric of power change per hour or acceleration in energy delivery.
3. Therefore, option (A) is correct.

In case of option D

1. $1hp=746W$.
2. Home appliances and many industrial appliances use this unit of power for rating electric appliances. The submersible pumps, well pumps, and other motors have power ratings given in $hp$.
3. Generally, we use the motors from $1hpto10hp$. Therefore, $hp$ is the practical unit of power.

The explanation of the incorrect option

In case of option B

1. $1MW=106W$.
2. The hot tub uses approximately $1MW$ of power. This unit of power is not used in daily life for rating the appliances.
3. Therefore, option (B) is incorrect.

In case of option C

1. $1GW=109W$.
2. This unit is used in large industries where the usage of electricity is at its peak. This unit of power is not used in daily life for rating the appliances.
3. Therefore, option (C) is incorrect.

Hence, options (A) and (D) are the correct answer.