A weightless rubber balloon has 100 gram of water in it. Its weight in water will be:

Options

A. (a)100 gram
B. (b)200 gram
C. (c)50 gram
D. (d)Zero

Explanation

To solve the problem of determining the weight of a weightless rubber balloon containing 100 grams of water when it is submerged in water, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Problem**:
We have a weightless rubber balloon filled with 100 grams of water. We need to find out what its weight will be when it is submerged in water.

2. **Weight Calculation in Air**:
The weight of the water inside the balloon can be calculated using the formula:
\[ \text{Weight} (W) = \text{mass} (m) \times \text{acceleration due to gravity} (g) \]
Here, the mass of the water is 100 grams, which is equivalent to 0.1 kg. The acceleration due to gravity (g) is approximately \(10 \, \text{m/s}^2\).
\[ W = 0.1 \, \text{kg} \times 10 \, \text{m/s}^2 = 1 \, \text{N} \]
So, the weight of the water in air is 1 N.

3. **Understanding Buoyancy**:
When the balloon is submerged in water, it experiences a buoyant force equal to the weight of the water displaced by the balloon. Since the balloon is filled with water, the volume of water displaced is equal to the volume of the balloon.

4. **Buoyant Force Calculation**:
The buoyant force (F_b) can also be calculated using the formula:
\[ F_b = \text{density of water} (\rho) \times \text{volume displaced} (V) \times g \]
The density of water is approximately \(1000 \, \text{kg/m}^3\). The volume of 100 grams of water is:
\[ V = \frac{m}{\rho} = \frac{0.1 \, \text{kg}}{1000 \, \text{kg/m}^3} = 0.0001 \, \text{m}^3 \]
Thus, the buoyant force is:
\[ F_b = 1000 \, \text{kg/m}^3 \times 0.0001 \, \text{m}^3 \times 10 \, \text{m/s}^2 = 1 \, \text{N} \]

5. **Net Weight in Water**:
The apparent weight of the balloon when submerged in water is given by the difference between the weight of the water inside the balloon and the buoyant force acting on it:
\[ \text{Apparent Weight} = W - F_b = 1 \, \text{N} - 1 \, \text{N} = 0 \, \text{N} \]

6. **Conclusion**:
Therefore, the weight of the balloon when it is submerged in water is **0 N**.

### Final Answer:
The weight of the rubber balloon with 100 grams of water in it when submerged in water is **0 N**.