Nanometers???

Question

Which of the following is not correct?

1 µm = 10-6 m
1 nm = 10-9 m
1 µm = 103 nm
1 µm = 10-3 mm
1 nm = 10-6 µm

Answer 1

The last one is wrong. According to the way you are writing them, 1nm = 10-3 um

Answer 2

The last one

Answer 3

Seems like you need to review the definitions of the prefixes