A 500W heater is used to heat 0.6kg of water from 25ºC to 100ºC in t\(_1\) seconds. If another 1000W heater is used to heat 0.2kg of water from 10ºC to 100ºC in t\(_2\), seconds, find \(\frac{t_1}{t_2}\)
50
5
5/4
1/5
Explanation
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p1=m1c1∆/t1.........(i) ∆ =change in temp. ∆2-∆1
p2=m2c2∆/t2........(i)
From equation (i)
500=0.6*75*c1*75/t1
cross multiplying
t1=45c/500
t1=0.09c
from eqtn (ii)
1000*t2=0.2*90
dividing through by 1000
t2=0.018
so t1/t2 = 0.09/0.018
t1/t2= 5
so 5 is correct.
I think none of the answers is right. Cause am getting totally different answers
totally wrong my school ......
500 x t2 = 0.6 x c x (100-25 )
500t2 = 0.6 x c x 75
t2 = 45c/500
t1
1000 x t1 = 0.2 x c x (100-10)
1000t1 = 0.2 x c x 90
t1= 18c /1000
to this question t1/t2
18c /1000 x 500/45c
9000c/45000c
1/5
The answer is 1/5 because t2 should be gotten first before t1. Then the question wants us to get t1/t2.
Then our value for t1 is 0.018
For t2 is 0.09.
Therefore, t1/t2
=0.018/0.09
=1/5
✌️
from Pt=Energy
500t2 = 0.6 x c x (100-25)
1000t1=0.2 x c x (100-10)
dividing t1 by t2 we should have
1000t1/500t2 =(0.2 x c x 90)/(0.6 x c x 75)
2t1/t2 = 18/45
t1/t2 = 1/5
The selected answer is wrong:
Misinterpretation of the question by the solver.
