Oh, and study for our Monday quiz. It's all that fun math stuff that we overstudied for in preparation of our last quiz. Ohm's Law, Watt's Law, $kWh and more!
Since I don't have anything particularly witty to say today, without further adieu, here is a bunny with a waffle on its head:
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ReplyDeleteany body has the answer for module 1 - Unit 4 & 5 question number 22,23,24.
ReplyDeleteMarcial, it's John. I'll help you out with these ones.
ReplyDeleteQuestion 22 in Module 1 says that there are 12 toasters, each drawing 11 amps.
1) What is the wattage (W) developed by each toaster?
Reasoning: We know that through Watt's Law that power (P) equals the product (multiplication) of Energy (E) and Intensity (I); otherwise written as P = E x I. Therefore, Wattage (W) equals Voltage (V) times amperage (A).
P = E x I --- P = 120V x 11A = 1320W.
2) Next, we are asked to find the total Wattage of all 12 toasters.
Reasoning: We know that each toaster develops 1320W of power, and we have 12 toasters. We simply multiply 1320W by 12 and get 15840W total for 12 toasters.
3) Finally, we are asked to find the resistance of each toaster.
Reasoning: We know that in combining Ohm's Law (E = I x R) and Watt's Law (P = E x I), that we discover new formulas to derive answers. To find resistance, we need to use the following:
R = E2 (squared) / P. Resistance equals Energy squared divided by Power. Therefore, R = 120 squared / 1320. R = 14400 / 1320 =10.909 ohms.
Each toaster has 10.91 ohms of resistance.
Question 23 tells you that you now have to answer the previous question using a new value of voltage, 60V.
ReplyDelete1) Twelve 60V toasters draw 11 amps each. Find the Wattage (W).
Reasoning: Follow the same steps as Question 22, using the new voltage amount given. P = E x I. Therefore, P = 60V x 11A = 660W. Remember that the values of voltage (V) and power (W) are directly proportional. If voltage is cut in half, power is cut in half as well.
2) Again, total wattage of the toasters is going to be figured out the same way. You can simply take your answer from Question 22 and divide it by 2. 15840 / 2 = 7920W.
3) Finding the resistance of each toaster is a exactly the same. We can use the same formula we used in the original question; R = E2 (squared) divided by P. Therefore, R = 3600 / 660 = 5.45 ohms. Notice that the resistance value was also cut in half.
Now we have to find the answer using the value of 240V.
ReplyDelete640
The exact same rules apply.
1) P = 240V x 11A = 2640W.
2) 2640W x 12 = 31680W
3) R = E2 (squared) / P. R = 21.82 ohms.
John, for question 23 and 24. The way i understand it is, it is still the same twelve 120v toaster, but now it is connected to a 60v source. I think this is where we use our friend which is the resistance. so this is what i did.
ReplyDeleteE=60v/12 toasters
E=5v
P=5v squared/10.91(resistance)
P= 2.291W each toaster
Ptotal= 2.291W x 12
Ptotal= 27.492
i did the same method for question 24 but using 240v instead of 60.
did i analyze the questions right?
Hey everybody!! Norm, John, or who's available today.. I lost my notes on all meter errors. Could anybody post all of them here or e-mail it to me on melsalazar77@hotmail.com.Pls. post all 6 of them. TY
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ReplyDeleteThose Ohms and Watts Law are kind of old school, wait till we get to Series Parallel Circuit Formulas. And Classmate, I'll give y'all a bonus on how to remember the "RESISTOR COLOR CODES" which are not on our books!!!! So REMEMBER THIS WORDS.....
ReplyDeleteBETTER - BLACK
BE - BROWN
RIGHT - RED
OR - ORANGE
YOUR - YELLOW
GREAT - GREEN
BIG - BLUE
VENTURE- VIOLET
GOES - GRAY
WRONG - WHITE
Remember this because I will not post this again.. You only got one glimpse of this, you snooze you lose.
Meter errors:
ReplyDeleteMulti-scale
interpolation
parallax
scale (full scale deflection)
I think we have only 4 meter errors