The magnitude of atmospheric pressure is equal to the pressure exerted by a :

Options

A. 76 mm tall column of mercury
B. 76 0 mm tall column of water
C. 76 cm tall column of mercury
D. 760 cm tall column of mercury.

Answer

To solve the question about the magnitude of atmospheric pressure and its equivalence to the pressure exerted by a column of mercury, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Atmospheric Pressure**: Atmospheric pressure is the force exerted by the weight of air above a surface. It can be measured using a column of liquid, typically mercury.

2. **Identify the Measurement Units**: Atmospheric pressure is commonly measured in millimeters of mercury (mmHg). The standard atmospheric pressure at sea level is defined as 760 mmHg.

3. **Convert Units**: Recognize that 760 mm is equivalent to 76 cm (since 1 cm = 10 mm). This means that the height of the mercury column that exerts the same pressure as the atmosphere is 76 cm.

4. **Relate Pressure to Height of Mercury Column**: The pressure exerted by a column of liquid is given by the formula:
\[ P = \rho g h \]
where \( P \) is the pressure, \( \rho \) is the density of the liquid (mercury in this case), \( g \) is the acceleration due to gravity, and \( h \) is the height of the liquid column.

5. **Conclusion**: Since the atmospheric pressure is equivalent to the pressure exerted by a 76 cm tall column of mercury, we can conclude that the correct answer is **Option 3: 76 centimeter tall column of mercury**.

### Final Answer:
The magnitude of atmospheric pressure is equal to the pressure exerted by a **76 centimeter tall column of mercury**.

---