The temperature difference in and outside an electric oven is 150oC glass fitted on the door has thickness and area of 0.2cm and 300cm2 respectively. if thermal conductivity of glass is 0.84Js-1m-1K-1 then how much heat will be lost in one minute?
(Area)*(Thermal conductivity)*(temperature difference)*(time)/(thickness) = __ J
Make sure you use meters and square meters for thickness and area, respectively. Time must be 60 s
Area=o.oo2m temperature difference=150oK thermal conductivity=0.84Js-1m-1K-1 thickness=0.03m time=60s ^=delta thermal conductivity=K A^T t\L 0.84*0.03*150*60\0.002=113400J
To calculate the heat lost in one minute, we need to use the formula:
Heat lost = (Thermal conductivity x Area x Temperature difference) / Thickness
Given:
Thermal conductivity (k) = 0.84 J/s*m*K
Area (A) = 300 cm^2 = 300 * 10^-4 m^2
Temperature difference (ΔT) = 150°C = 150 K
Thickness (L) = 0.2 cm = 0.2 * 10^-2 m
Let's substitute these values into the formula:
Heat lost = (0.84 J/s*m*K) x (300 * 10^-4 m^2) x (150 K) / (0.2 * 10^-2 m)
Simplifying the expression:
Heat lost = (0.84 x 300 x 150) / (0.2)
Heat lost = (37800) / (0.2)
Heat lost = 189,000 J/s
Since we want to find the heat lost in one minute, we need to convert the time unit:
Heat lost = 189,000 J/s x 60 s
Heat lost = 11,340,000 J
Therefore, the heat lost in one minute is 11,340,000 Joules.