Question

which of the following is most appropriate to describe the average distance from earth to the sun?
a) 1.5×10¹⁴ mm
b) 1.5×10¹³ cm
c) 1.5×10¹¹ m
d) 1.5×10⁸ km

Explanation:

Step1: Convert all units to meters

• For option A:

Since \(1\space mm = 10^{- 3}\space m\), then \(1.5\times10^{14}\space mm=1.5\times10^{14}\times10^{-3}\space m = 1.5\times10^{11}\space m\)

• For option B:

Since \(1\space cm=10^{-2}\space m\), then \(1.5\times 10^{13}\space cm = 1.5\times10^{13}\times10^{-2}\space m=1.5\times10^{11}\space m\)

• For option C:

\(1.5\times10^{11}\space m\) (already in meters)

• For option D:

Since \(1\space km = 10^{3}\space m\), then \(1.5\times10^{8}\space km=1.5\times10^{8}\times10^{3}\space m=1.5\times10^{11}\space m\)

Step2: Recall the average Earth - Sun distance

The average distance from Earth to the Sun is approximately \(1.5\times10^{11}\space m\)

Answer:

C. \(1.5\times 10^{11}\space m\)