We are asked to determine which device would Jessica needs to make the measurement in each statement given that the statements are all true.
Recall the rules on significant figures:
1. All non-zero numbers ARE significant. The number 33.2 has THREE significant figures because all of the digits present are non-zero.
2. Zeros between two non-zero digits ARE significant. 2051 has FOUR significant figures. The zero is between a 2 and a 5.
3. Leading zeros are NOT significant. They're nothing more than "place holders." The number 0.54 has only TWO significant figures. 0.0032 also has TWO significant figures. All of the zeros are leading.
4. Trailing zeros to the right of the decimal are significant. There are FOUR significant figures in 92.00.
5. Trailing zeros in a whole number with the decimal shown ARE significant. Placing a decimal at the end of a number is usually not done. By convention, however, this decimal indicates a significant zero. For example, "540." indicates that the trailing zero IS significant; there are THREE significant figures in this value.
6. Trailing zeros in a whole number with no decimal shown are NOT significant. Writing just "540" indicates that the zero is NOT significant, and there are only TWO significant figures in this value.
7. Exact numbers have an INFINITE number of significant figures. This rule applies to numbers that are definitions. For example, 1 meter = 1.00 meters = 1.0000 meters =
1.0000000000000000000 meters, etc.
8. For a number in scientific notation: N x 10x, all digits comprising N ARE significant by the first 6 rules; "10" and "x" are NOT significant. 5.02 x 104 has THREE significant figures: "5.02." "10 and "4" are not significant.