Which one among the following measures the same quantity as that is measured by the SI unit 'pascal'?
Answer & explanation
Correct answer: option 2
The correct answer is option 2. torr.
Out of the choices you provided, the unit that measures the same quantity as the SI unit pascal (Pa) is torr.
Pascal (Pa): It is the SI unit of pressure. Pressure is defined as force (measured in newtons) exerted per unit area. So, 1 Pa is equal to 1 newton per square meter (N/m²).
Torr: It is a non-SI unit of pressure commonly used in some scientific fields, particularly vacuum technology.
Conversion between Pascal and Torr:
1 torr is defined as 1/760 of a standard atmosphere (atm). We know that 1 atm is equal to 101325 Pa. Therefore:
\(1 \text{ torr} = (\frac{1}{760} atm) × (101325 Pa\text{ atm}^{-1}) ≈ 133.32 Pa\)
Other options:
Watt (W): This unit measures power, which is the rate of doing work (energy) per unit time. It's not the same as pressure.
Newton (N): This unit measures force, another distinct quantity from pressure.
Joule (J): This unit measures energy, not pressure.