A partially inflated balloon is placed inside a bell jar connected to a vacuum pump. On creating vacuum inside the bell jar, balloon gets more inflated. How does the pressure change : increase, decrease or remains same, inside the (a) bell jar and (b) balloon ?

Answer

To solve the question regarding the changes in pressure inside a bell jar and a balloon when a vacuum is created, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Initial Conditions**:
- Initially, the balloon is partially inflated and placed inside a bell jar. The pressure inside the balloon is higher than the atmospheric pressure outside the jar.

2. **Creating a Vacuum**:
- When the vacuum pump is activated, it removes air from the bell jar. This action decreases the pressure inside the bell jar significantly.

3. **Pressure Comparison**:
- At the moment the vacuum is created, the pressure inside the bell jar becomes lower than the pressure inside the balloon. This is because the balloon still contains air at a higher pressure than the now-vacuumed bell jar.

4. **Equilibrium Condition**:
- For the balloon to maintain its shape and size, the pressures inside the balloon and the bell jar must equalize. Since the pressure in the bell jar is now lower, the balloon will expand to equalize the pressure difference.

5. **Pressure Changes**:
- **(a) Inside the Bell Jar**: The pressure decreases as air is removed, creating a vacuum.
- **(b) Inside the Balloon**: The pressure inside the balloon decreases as it expands to fill the space and equalize with the lower pressure in the bell jar.

### Final Answer:
- (a) The pressure inside the bell jar **decreases**.
- (b) The pressure inside the balloon **decreases**.