A certain part of a computer chip has a length of 1.5 micrometers. How many meters is this?

When you're working with units of measure, "micro" almost always means "millionth", or 1 x 10⁻⁶. And that's exactly the case in this example.

"1.5 micrometer" = 1.5 millionths of a meter, or 1.5 x 10⁻⁶ meter.