The average size of the colloids is of the order 

Options

A. `10^(-12)M" to "10^(-19)m`
B. `10^(-7)m" to "10^(-9)m`
C. `10^(-9)m" to "10^(-12)m`
D. `10^(-6)m" to "10^(-9)m`

Answer

To determine the average size of colloids, we can follow these steps:

### Step 1: Understand the Size Range of Colloids
The average size of colloidal particles is typically in the range of \(10^{-5}\) cm to \(10^{-7}\) cm.

### Step 2: Convert Centimeters to Meters
To convert the sizes from centimeters to meters, we use the conversion factor \(1 \text{ cm} = 10^{-2} \text{ m}\).

- For \(10^{-5}\) cm:
\[ 10^{-5} \text{ cm} = 10^{-5} \times 10^{-2} \text{ m} = 10^{-7} \text{ m} \]

- For \(10^{-7}\) cm:
\[ 10^{-7} \text{ cm} = 10^{-7} \times 10^{-2} \text{ m} = 10^{-9} \text{ m} \]

### Step 3: State the Size Range in Meters
After conversion, the average size of colloidal particles is in the range of:
\[ 10^{-7} \text{ m} \text{ to } 10^{-9} \text{ m} \]

### Step 4: Identify the Correct Answer
Based on the given options, the average size of colloids falls within the range of \(10^{-7} \text{ m}\) to \(10^{-9} \text{ m}\).

### Final Answer
The average size of colloids is in the order of \(10^{-7} \text{ m}\) to \(10^{-9} \text{ m}\).

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