Answer:
a) 35 s
b) 39 s
Explanation:
Initial temperature T₁= 20 °C
Final temperature T₂= 90 °C
Temperature rise rate = 2 °C/s
To solve the problem we can use the formula T₁ + t * 2°C/s = T₂
Where t is the time, in seconds.
We solve for t :
20°C + t * 2°C/s = 90°C
t * 2°C/s = 70°C
t = 35 s
20°C + t * 2°C/s = 98°C
t * 2°C/s = 78°C
t = 39 s