Question

Calculate the efficiency of a hair dryer which takes in 4500J of energy per second and transfers 150J as useful heat energy.

Answer 1

η = 0.0333 = 3.33 %

Step-by-step explanation:

The efficiency of any device is defined as the ratio of the useful output obtained from that device to the input required by the device. Therefore, the general formula to find the efficiency of any device is given as follows:

`\eta = (O)/(I)`

where,

η = efficiency of hair dryer = ?

O = Useful Output Given by the Hair Dryer = 150 J

I = Input Energy Required by the Hair Dryer = 4500 J

Therefore,

`\eta = (150\ J)/(4500\ J)\\`

η = 0.0333 = 3.33 %