3E8

3E8 is a numeric expression written in scientific notation, representing the value 3 × 10^8. In decimal form, this equals 300,000,000. The notation is commonly used in scientific, engineering, and computational contexts to express large or small numbers succinctly.

In physics, 3×10^8 m/s is a common rough magnitude assigned to the speed of light in vacuum, denoted by c. The exact SI value of the speed of light is 299,792,458 meters per second, so 3×10^8 m/s is an approximation often used for simplicity in calculations and explanations. In other units, 3E8 m/s converts to about 300,000 kilometers per second.

In computing and programming, 3e8 or 3E8 is a floating-point literal used to represent the same numeric value. Depending on the language, it is parsed as a floating-point number (such as a double or float) and can participate in arithmetic like any other real number. For example, in many languages, 3e8 evaluates to 300000000.0. The precision and behavior of such literals are subject to the language’s numeric type system and floating-point arithmetic.

The E notation (with E or e) indicates an exponent of ten. Values written in this form can be scaled by the exponent efficiently and are widely supported in calculators, programming languages, and data formats. While 3E8 is convenient for quick representation, it is an approximation when used to denote physical constants, and the exact value should be used when high precision is required.