physics.heat problems!please!quite urgent.
there are lots of qustions asking that "the result obtained will be larger or smaller than the true value of x if....."
i dunno why i'm always wrong in answering this type of question
i really so confused.
there's an experiment to find the specific latent heat of vaporization of water
determine if the result obtained will be larger or smaller than the true value of l(v) if
(i) measurement is started before the water boils
(ii)some steam condenses and drips back into the beaker
(iii) some boiling water inside the beaker splashes out of the beaker
answer(i) is larger
as E=ml and E=pt, doesnt it mean l=pt/m?
in situation (i),i understand this one
measurement starts earlier and measured energy is larger
so l becomes larger at the same time
answer(ii) is larger
i dont understand this one because as the mass becomes larger
is that l will become smaller too?(l=E/m)
answer(iii) is smaller
and yes i understand this one too
but how about (ii)?
- 天同Lv 71 十年 前最佳解答
When evapourated water condensed and dripped back into the beaker, the final mass of water left in the beaker is larger than it should be if no condensation occurred.
Since m in your equation is the mass of water evapourated, which is calculated by subtracting the final mass from the initital mass of water in the beaker,
i.e. m = mass(initial) - mass(final)
Since latent heat = energy supplied E/m
now, because m(finial) is larger, then m becomes smaller than it should be. The calculated latent heat is larger than the actual value.