The temperature of a substance decreases at the rate of 2℃ per 10 minutes. The temperature of the substance at 5 o'clock was 10℃. At what time will the temperature of the substance be 4℃ below zero?
Answers
Answer:
At "6:10" the temperature will be -4°C
Step-by-step explanation:
Solution:
We can form the following table
TIME PASSED IN MINUTES : TEMPERATURE
0 10°C
10 8°C
20 6°C
30 4°C
40 2°C
50 0°C
60 -2°C
70 -4°C
As we are given that temperature is 10°C at 5 :00 and we see in the table the temperature will be -4°C after passing 70 minutes.
So
4°C below zero (degree) means -4°C
because
0°C - 4°C= -4°C ( not 4°C)
The time at which temperature is -4°C = 5 :00 +70 minutes
= 5:00 + 1:10
= 6:10
Hence "6 : 10" is required time.
Answer:
Cooling rate = 0.2°C/min
Temperature at 5 pm = 10°C
Time for a temperature drop of 1°C = ?
If the substance takes 10 minutes for a 2°C drop (given),
it will take 5 mins for a drop of 1°C.
Therefore, for 14°C temperature drop,
It would take 5x14 = 70 minutes
Time by which temperature goes below 4°C = 6:10 pm