Question

$\textsf{Find\: the\:change\: in\: internal\: energy \:of\: the \:system\: when\: a \:system\: absorbs\: 2\: kilo\: calorie\: of \:heat \:and\: at\: same\: time\: does\: 500\: joules \:of \:work:}$
(A)7900J
(B)8200J
(C)5900J
(D)6400J
_______________
don't answer only for points.
solve it!

Answer 1

$\underline {\bold {HEYA!!}}$

∆Q = ∆U + ∆W

therefore, ∆U = ∆Q + ∆W

here, ∆Q = 2KCal = 2000cal

= 2000 × 4.2J

= 8400J

therefore,∆U = 8400 - 500 = 7900J

________________

Answer 2

$<u><b><i>∆Q=∆U+∆W .•.,∆U=∆Q+∆W ∆Q=2KCAL=2000cal 2000=4.2J =8400J .•.,∆U=8400-500 =7900J$

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