A glass plate of length 10 cm, breadth 4 cm, and the thickness 0.4cm , weighs 20g in air. It is held vertically with long side horizontal and half the plate immersed in water. What will be its apparent weight? Surface tension of water = `70 dyn e//cm`.

Explanation

To find the apparent weight of the glass plate when it is half immersed in water, we will follow these steps:

### Step 1: Calculate the weight of the glass plate in Newtons
The weight (W) of the glass plate can be calculated using the formula:
\[ W = mg \]
where:
- \( m = 20 \, \text{g} = 0.02 \, \text{kg} \) (conversion from grams to kilograms)
- \( g = 10 \, \text{m/s}^2 \) (acceleration due to gravity)
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