SI prefix
A standardised multiplier applied to SI units to express values over a wide range of magnitudes. Common prefixes include kilo- (10³), mega- (10⁶), giga- (10⁹), milli- (10⁻³), micro- (10⁻⁶), nano- (10⁻⁹), and pico- (10⁻¹²). Each prefix represents a fixed power of 10.
Real World
Apple's M2 chip operates at 3.49 GHz, meaning its clock ticks 3.49 × 10⁹ times per second — the giga- prefix turns an unwieldy number into something readable on a spec sheet.
Exam Focus
Convert all values to SI base units before substituting into equations — mark schemes penalise answers with unconverted prefixes.
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