Question

How much power is used by a contact lens heating unit that draws 0.05 A of current from a 197 V line?

Answer 1

Given,

The current drawn by the contact lens heating unit, I=0.05 A

The supply voltage, V=197 V

The electric power is given by the product of the current drawn and the supply voltage.

Thus the power used by the given device is given by,

`P=VI`

On substituting the known values,

`\begin{gathered} P=197*0.05 \\ =9.85\text{ W} \end{gathered}`

Thus the power used by the contact lens heating unit is 9.85 W