Question

A grain has a size of 36 mm when observed under a magnification of 125 times. The actual size of the grain in µm is ............. (In integer)

Hint:

To find the actual size from the observed size, divide the observed size by the magnification factor. Remember to convert units as necessary.

Answer 1

Step 1: Understand the problem.
The given size of the grain is 36 mm under a magnification of 125. This means that the actual size is smaller than the observed size by a factor of 125.
Step 2: Convert the size to µm.
To get the actual size in micrometers (µm), we first convert 36 mm to µm: \[ 1 \, \text{mm} = 1000 \, \mu m \] So, 36 mm = \( 36 \times 1000 = 36000 \, \mu m \). Step 3: Calculate the actual size.
Now, divide the observed size by the magnification factor: \[ \text{Actual size} = \frac{\text{Observed size}}{\text{Magnification factor}} = \frac{36000 \, \mu m}{125} \] \[ \text{Actual size} = 288 \, \mu m \] Final Answer: \[ \boxed{288} \]