Question

The power supplied to a typical black-and-white television set is 90 W when the set is connected to 120 V. (a) How much electrical energy does this set consume in 1 hour? (b) A color television set draws about 2.5 A when connected to 120 V. How much time is required for it to consume the same energy as the black-andwhite model consumes in 1 hour?

Answer 1

The electrical energy and time required for it to consume the same energy are
`3.24*10^(5)\ J` and 18 min.

Step-by-step explanation:

Given that,

Power = 90 W

Voltage V = 120 V

Current = 2.5

(a). We need to calculate the amount of energy

Using formula of energy

`Q=pt`

Where, p = power

t = time

Put the value into the formula

`Q=90*1`

`Q=90*3600`

`Q=3.24*10^(5)\ J`

(b). We need to calculate the power

Using formula of power

`P=V* I`

Where, I = current

V = voltage

Put the value into the formula

`P=120*2.5`

`P=300\ W`

We need to calculate the time

Using formula of time

`t= (Q)/(P)`

Put the value into the formula

`t=(3.24*10^(5))/(300)`

`t=1080\s`

`t=(1080)/(60)=18\ min`

Hence, The electrical energy and time required for it to consume the same energy are
`3.24*10^(5)\ J` and 18 min.