Question

6. In a Microbiology laboratory, certain tests are done under controlled temperature. The variation
in temperature is by fixed number of degrees per minute. Evaluate each of the following:
(a) The temperature at the beginning of an experiment is 20°C. It increases by 4°C per minute.
What is the temperature at the end of the experiment if it took 15 minutes to complete?
(b) The temperature is made to fall by 3°C per minute. The temperature at the end of an
experiment is -7°C, which took 13 minutes to complete. What was the temperature at
the beginning of the experiment?



Please give me the answer


with explain



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Answer 1

The temperature at the beginning of expt = 20°c.

Rate of temperature increase = 4°c per min

Time for completion of expt = 15 min

Total rise in temperature = 15 × 4 = 60℃

Temperature at the end of the experiment

= 20+60 = 80℃

b)

Rate of fall of temperature = 3℃ per min.

Temperature at the end of an experiment = -7℃

Time for completion of expt = 13 min

Total fall in temperature = 13 × 3 = 39℃

Let the starting temperature be x ℃

=>x - 39 = -7

=> x = -7 + 39 = 32℃

Temperature at the beginning of the experiment was 32℃