Q1: A 25 cm x 25 cm x 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1m x 1m x 1cm flat sheet of the same material is to be dried from one side only.Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is

ANS:A - 1000

To solve this problem, we can use the concept of similarity between the two sheets. The ratio of their initial weights will be the same as the ratio of their drying times. Given:

• Initial weight of the first sheet (𝑊1W1​) = 1.2 kg
• Final weight of the first sheet (after drying) (𝑊2W2​) = 1.05 kg
• Initial weight of the second sheet (𝑊1′W1′​) = 19.2 kg
• Final weight of the second sheet (after drying) (𝑊2′W2′​) = 17.6 kg
• Time taken to dry the first sheet (𝑡t) = 1500 seconds

First, let's calculate the weight reduction ratio for the first sheet: Weight Reduction Ratio=𝑊1−𝑊2𝑊1=1.2−1.051.2=0.151.2Weight Reduction Ratio=W1​W1​−W2​​=1.21.2−1.05​=1.20.15​ Now, let's use the weight reduction ratio to find the final weight of the second sheet after drying: 𝑊2′=𝑊1′−(Weight Reduction Ratio×𝑊1′)W2′​=W1′​−(Weight Reduction Ratio×W1′​) 𝑊2′=19.2−(0.151.2×19.2)W2′​=19.2−(1.20.15​×19.2) 𝑊2′=19.2−2.4=16.8 kgW2′​=19.2−2.4=16.8 kg Now, we can find the time taken to dry the second sheet using the ratio of initial weights: Time Ratio=𝑊1′𝑊1=19.21.2=16Time Ratio=W1​W1′​​=1.219.2​=16 Time taken to dry the second sheet=Time Ratio×𝑡Time taken to dry the second sheet=Time Ratio×t Time taken to dry the second sheet=16×1500=24000 secondsTime taken to dry the second sheet=16×1500=24000 seconds So, the time required for drying the second sheet from its initial weight of 19.2 kg to 17.6 kg under the same constant drying rate conditions is 24000 seconds, which is not among the provided options. It seems there might have been a misinterpretation of the problem. Let's correct it and try again.