Working of paint-gun and scent sprayer is based on :-

Options

A. Bernoulli's principle
B. Boyle's law
C. Faraday's law
D. Archimedes' principle

Answer

To solve the question regarding the working of a paint gun and scent sprayer, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Mechanism**:
- A paint gun and scent sprayer both utilize a mechanism that involves the movement of liquid through a nozzle. The liquid is drawn up from a reservoir and expelled through a nozzle when a bulb or trigger is pressed.

2. **Identifying the Components**:
- The main components include:
- A tube that holds the liquid (paint or scent).
- A bulb or trigger that, when pressed, creates a change in pressure.
- A nozzle through which the liquid is expelled.

3. **Pressure Change**:
- When the bulb is squeezed, air is forced into the tube, which creates a decrease in pressure at the point of the nozzle. According to the principles of fluid dynamics, this pressure difference causes the liquid to rise in the tube.

4. **Bernoulli's Principle**:
- The working of these devices can be explained using Bernoulli's principle, which states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure.
- Mathematically, Bernoulli's equation is given by:
\[ P + \rho g h + \frac{1}{2} \rho v^2 = \text{constant} \]
- Here, \( P \) is the pressure, \( \rho \) is the fluid density, \( g \) is the acceleration due to gravity, \( h \) is the height, and \( v \) is the velocity of the fluid.

5. **Application of Bernoulli's Principle**:
- As the pressure decreases at the nozzle (due to the air being blown in), the velocity of the liquid increases. This results in the liquid being pushed out of the nozzle because the outside atmospheric pressure is higher than the pressure inside the tube.

6. **Conclusion**:
- Therefore, the working of both the paint gun and the scent sprayer is based on Bernoulli's principle, which explains the relationship between pressure and velocity in fluid dynamics.

### Final Answer:
The working of a paint gun and scent sprayer is based on **Bernoulli's principle**.