View Full Version : Electric Currents
fainah
Feb 12, 2012, 10:06 AM
The total current delivered to a number of devices connected in parallel is the sum of the individual currents in each device. Circuit breakers are resettable automatic switches that protect against a dangerously large total current by "opening" to stop the current at a specified safe value. A 1500 W toaster, a 1020 W iron, and a 1250 W microwave oven are turned on in a kitchen. As the drawing shows, they are all connected through a 20 A circuit breaker to an ac voltage of 120 V.
(a) Find the equivalent resistance of the three devices._________Ohms
(b) Obtain the total current delivered by the source._____________A
(c) Determine whether the breaker will "open" to prevent an accident.
(The breaker will "open") OR (The breaker will remain "closed") ?
fainah
Feb 12, 2012, 10:08 AM
Two resistors, 58.0 Ohms and 58.0 Ohms , are connected in parallel. The current through the second resistor is 4.40 A.
(a) What is the current in the first resistor?_______A
(b) What is the total power supplied to the two resistors?________W
fainah
Feb 12, 2012, 10:09 AM
The drawing shows a circuit that contains a battery, two resistors, and a switch. Consider the circuit with R1 = 67.5, R2 = 98.1, and V = 9.7.
(a)What is the equivalent resistance of the circuit when the switch is open and closed?
Ropen____________ = Ω
Rclose____________ = Ω
(b) What is the total power delivered to the resistors when the switch is open and closed?
Ropen____________ = W
Rclose____________ = W
fainah
Feb 12, 2012, 10:09 AM
For a three-way bulb (60 W, 100 W, 160 W) that is designed to operate at 120 V, find the resistance of each of the two filaments. Assume that the wattage ratings are not limited by significant figures and ignore any heating effects on the resistances.
60 W filament________Ohms
100 W filament__________Ohms
fainah
Feb 12, 2012, 10:10 AM
A 8 Ohms loudspeaker and a 8 Ohms loudspeaker are connected in parallel across the terminals of an amplifier. Assuming the speakers behave as resistors, what is the equivalent resistance of the two speakers?
_____________Ohms
fainah
Feb 12, 2012, 10:11 AM
A 13 Ohms coffee maker and a 16 Ohms frying pan are connected in series across a 120 V source of voltage. A 26 Ohms bread maker is also connected across the 120 V source and is in parallel with the series combination. Find the total current supplied by the source of voltage._______________A
fainah
Feb 12, 2012, 10:12 AM
A 58.0 Ohms resistor is connected in parallel with a 124.0 Ohms resistor. This parallel group is connected in series with a 19.0 Ohms resistor. The total combination is connected across a 15.0 V battery.
(a) Find the current in the 124.0 Ohms resistor. ___________A
(b) Find the power dissipated in the 124.0 Ohms resistor.____________W
fainah
Feb 12, 2012, 10:12 AM
Three identical resistors are connected in parallel. The equivalent resistance increases by 650 Ohms when one resistor is removed and connected in series with the remaining two, which are still in parallel. Find the resistance of each resistor.____________Ohms
fainah
Feb 12, 2012, 10:13 AM
What resistance must be placed in parallel with a 157 Ohms resistor to make the equivalent resistance 113 Ohms ? ____________Ohms
fainah
Feb 12, 2012, 10:20 AM
For the combination of resistors shown in the drawing (R1 = 43Ohms , R2 = 85Ohms ), determine the equivalent resistance between points A and B. __________Ohms
Curlyben
Feb 12, 2012, 10:20 AM
Please refer to this announcement
Do not simply retype or paste a question from your book or study material
We won't do your homework questions for you.
You were given the assignment for you to learn.
If you come up with your own answer and post it for us to critique that is within reason.
If you have some SPECIFIC questions that you couldn't find or didn't understand, we may help with that.
But this is your assignment, so show us you have at least attempted to complete it on your own.
Thank you.