Let's tackle the given problem step-by-step.
### Question i: Identifying the Media
First, we need to determine which medium corresponds to air, water, and salt solution.
From the given weights:
- Medium A: [tex]\(16 \, N\)[/tex]
- Medium B: [tex]\(18 \, N\)[/tex]
- Medium C: [tex]\(15 \, N\)[/tex]
- In air, the weight should be the highest because there is no buoyant force acting on the stone.
- In water, the weight is less due to the buoyant force exerted by the water.
- In salt solution, the weight is the least because the buoyant force exerted by the salt solution is greater than water.
So:
- Medium B (with weight [tex]\(18 \, N\)[/tex]) is air.
- Medium A (with weight [tex]\(16 \, N\)[/tex]) is water.
- Medium C (with weight [tex]\(15 \, N\)[/tex]) is the salt solution.
### Question ii: Mass of the Stone
We are given that the weight of [tex]\(1 \, kg\)[/tex] of mass in air is [tex]\(10 \, N\)[/tex].
1. The weight of the stone in air is [tex]\(18 \, N\)[/tex].
2. Using the relationship [tex]\( \text{Weight} = \text{Mass} \times \text{Gravitational Acceleration} \)[/tex], where gravitational acceleration is [tex]\(10 \, N/kg\)[/tex], we can find the mass of the stone.
[tex]\[
\text{Mass of the stone} = \frac{\text{Weight in air}}{\text{Gravitational acceleration}}
\][/tex]
[tex]\[
\text{Mass of the stone} = \frac{18 \, N}{10 \, N/kg} = 1.8 \, kg
\][/tex]
Thus, the mass of the stone is [tex]\(1.8 \, kg\)[/tex].
### Question iii: Mass of Water Displaced
To find the mass of the water displaced by the piece of stone, we need to consider the weight loss of the stone when it is submerged in water.
1. The weight loss in water is the difference between the weight in air and the weight in water.
2. The weight in air is given as [tex]\(18 \, N\)[/tex] and the weight in water is [tex]\(16 \, N\)[/tex].
[tex]\[
\text{Weight loss in water} = \text{Weight in air} - \text{Weight in water}
\][/tex]
[tex]\[
\text{Weight loss in water} = 18 \, N - 16 \, N = 2 \, N
\][/tex]
3. The weight loss corresponds to the weight of the water displaced. Since [tex]\(1 \, kg\)[/tex] of water has a weight of [tex]\(10 \, N\)[/tex], we can find the mass of the water displaced.
[tex]\[
\text{Mass of water displaced} = \frac{\text{Weight loss in water}}{\text{Gravitational acceleration}}
\][/tex]
[tex]\[
\text{Mass of water displaced} = \frac{2 \, N}{10 \, N/kg} = 0.2 \, kg
\][/tex]
Thus, the mass of the water displaced by the stone is [tex]\(0.2 \, kg\)[/tex].
### Summary of Answers:
i. Medium B is air, Medium A is water, Medium C is salt solution.
ii. The mass of the stone is [tex]\(1.8 \, kg\)[/tex].
iii. The mass of the water displaced by the stone is [tex]\(0.2 \, kg\)[/tex].
