Final answer:
The difference between the apparent magnitude and the absolute magnitude is known as the distance modulus. This difference can be used to calculate the distance to a star using the distance modulus formula.
Step-by-step explanation:
The difference between the apparent magnitude and the absolute magnitude is known as the distance modulus. The apparent magnitude is a measure of how bright a star appears from Earth, while the absolute magnitude is a measure of how bright a star would appear at a standard distance of 10 parsecs. The difference between these two magnitudes can be used to calculate the distance to a star using the distance modulus formula: Distance Modulus = Apparent Magnitude - Absolute Magnitude. This formula takes into account the dimming effects of distance on light and allows astronomers to estimate the distance to stars.