Question

An 1800-W toaster, a 1400-W speaker, and a 75-W lamp are plugged into the same outlet in a 15-A fuse and 120-V circuit. (The three devices are in parallel when plugged into the same socket.) (a) What current is drawn by each device

Answer 1

Step-by-step explanation:

Given that,

Power of the toaster,
`P_1=1800\ W`

Power of the speaker,
`P_2=1400\ W`

Power of the lamp,
`P_1=75\ W`

Current in the fuse, I = 15 A

Voltage, V = 120 V

To find,

The current is drawn by each device.

Solution,

In parallel combination of resistors, current flowing through every resistor divides while the voltage remains the same. The product of current and voltage is equal to the power delivered. It is given by :

`P=I* V`

Current in toaster,

`I_1=(P_1)/(V)`

`I_1=(1800)/(120)`

`I_1=15\ A`

Current in speaker,

`I_2=(P_2)/(V)`

`I_2=(1400)/(120)`

`I_2=11.67\ A`

Current in lamp,

`I_3=(P_2)/(V)`

`I_3=(75)/(120)`

`I_3=0.625\ A`

So, the current flowing through toaster, speaker and the lamp is 15 A, 11.67 A and 0.625 A respectively.