At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
This is a hint to an assignment I am currently doing.
I haven't read thru the textbook much or my notes; I'ved tried, and instead made a formula sheet, although I don't know what formula to apply to this.
use \[E = mc \theta \] Since there r lot of data this one can be use easily ... I think u should be familiar with this...
Actually, haven't seen this in my formula sheet. But I'll try it out.
wt's the value of "required no.of degrees" mentioned in the question ?
then I think u can use a relationship with ratios to solve this one cause the problem says "Multiply carefully to find " which mean question doesn't expect use of any formula instead it expect to build the answer from given data... change of 1 degree in 1ml = 4.2 J change of 1 degree in 2ml = 8.4 J change of 1 degree in 200 ml = 8.4*100 J
These are the answers that I gave to the work, which it stated was incorrect. It requires 3 significant figures. Submitted Answers ANSWER 1: Deduction: -3% "what you get" = 8.4⋅102 J ANSWER 2: Deduction: -3% "what you get" = 8.40⋅102 J
the 102 is suppose to be 10^2
So yes, I did use your answer, but apparently it was incorrect here.
It requires 3 significant figures. = is it same for the 840 J ?
wouldn't 8.40*10^3 J have worked?
Because 840 is only 2 sig digs without using a decimal point
no .. I just told that 'cause it's the same answer I get even if I use E = mc*theta
So, both answers would be considered incorrect with this question then?
@ganeshie8 , @thomaster
I managed to get the question after that correct, if it helps at all.
if 840 J is wrong .... there is one possible reason: we calculate 840 J to a temp. change of 1 degree. But the question asks the energy need for a temp. change of required no. of degrees. And we assume that is also as 1 degree. But this question has a section name part A. Does that part mention about some reading of temperature regarding this coffee cup
Yes. This is a 'hint' to a larger question.
Suppose that you have left a 200-mL cup of coffee sitting until it has cooled to 30∘C , which you find totally unacceptable. Your microwave oven draws 1100 W of electrical power when it is running. If it takes 45 s for this microwave oven to raise the temperature of the coffee to 60∘C , what is the efficiency of heating with this oven? Find the efficiency e of the oven. You will need to use the fact that 4.2 J of energy is required to raise the temperature of 1.0 mL of coffee by 1.0∘C .
yo ... that's the missing point!
the temperature of the coffee cup was 30 degree at the beginning and it has to be increased up to 60 degree
But I dunno if those 2 questions are directly related/
So we must calculate energy need to change the heat of 200ml by 30 degree
not just by one degree which is 840 J instead it should be 8.4*30 * 100 J which is 252*100 J and it also satisfy the condition of 3 digit ... try that one!
I've got 2 tries left. i'll test it out
wt happened ?
err sorry. i'm asking this question on several different mediums, and i'm just 'cross referencing'
Err, 8.4*30 * 100 J looks like \[8.4*10*100\] 252*100 J looks like \[252*100\]
Because if that was true, wouldn't that make the question incorrect?
srry.. could u explain it more ... it's not clear
The stars; do they represent the 'multiply' or the 'exponent' function?