The order of the magnitude of speed of light in SI unit is

Options

A. 16
B. 8
C. 4
D. 7

Answer

To determine the order of magnitude of the speed of light in SI units, we follow these steps:

### Step 1: Identify the value of the speed of light
The speed of light (denoted as \( c \)) is a known constant. In SI units, it is approximately:
\[ c = 3 \times 10^8 \text{ meters per second} \]

### Step 2: Understand the concept of order of magnitude
The order of magnitude of a number is the power of 10 when the number is expressed in scientific notation. It gives a rough estimate of the scale or size of the number.

### Step 3: Analyze the scientific notation
In the expression \( 3 \times 10^8 \), the significant part is the \( 10^8 \). The exponent (8) indicates the order of magnitude.

### Step 4: Conclude the order of magnitude
Since the speed of light is expressed as \( 3 \times 10^8 \), the order of magnitude is simply the exponent of 10, which is:
\[ \text{Order of magnitude} = 8 \]

### Final Answer
Thus, the order of magnitude of the speed of light in SI units is:
**8**