High School

Calculate the efficiency of a hair dryer which takes in 3000 J of energy per second and transfers 600 J as useful heat energy.

Answer :

Answer:

The efficiency of the hair dryer is 0.2 or 20%

Explanation:

The efficiency of a machine or any appliance is a measure of the useful work done by the machine when an effort is applied to the machine. The higher the efficiency of a machine, the more useful work the machine does.

Due to the economical and environmental impact of energy production, machines and appliances of high efficiency are being developed and recommended for domestic as well as industrial use nowadays.

In electrical appliances, energy is usually supplied by electrical power units. The higher the efficiency of an electrical appliance, the less power it consumes to do useful work. For a hair dryer which takes in 3000 J of energy per second and transfers 600 J of useful heat energy, its efficiency is calculated with formula below:

efficiency = useful energy / total energy input

Efficiency = 600 J / 3000 J = 0.2

Therefore, the efficiency of the hair dryer is 0.2 or 20%

The efficiency of the hair dryer is calculated using the ratio of the useful energy output to the total energy input. With an input of 3000J and a useful output of 600J, the efficiency is 20%.

To calculate the efficiency of a hair dryer that takes in 3000J of energy per second and transfers 600J as useful heat energy, we can use the formula for efficiency (E) which is the ratio of the useful energy output (useful heat energy) to the total energy input, multiplied by 100 to get a percentage:

E = (useful energy output / total energy input)
100%

In this case, the useful energy output is 600J and the total energy input is 3000J per second. Substituting these values into the formula gives:

E = (600J / 3000J)

100%

E = 0.2

100%

E = 20%

Therefore, the efficiency of the hair dryer is 20%.