Question

1. how is the exponent determined in scientific notation?

by counting the significant figures.
by dividing the number by 10.
by counting the number of places the decimal is moved.
by counting zeros in the number.

1. how many significant figures does 560 have?

0
2
1
3

1. what is the purpose of unit conversion in science?

to increase the precision of a measurement.
to change the unit of a measurement without changing its value.
to change the value of a measurement.
to reduce the number of significant figures.

Explanation:

Question 7

In scientific notation (\(a\times10^{n}\), where \(1\leq|a|\lt10\)), the exponent \(n\) is determined by counting how many places the decimal point is moved to get \(a\) from the original number. Counting significant figures is for significant figures, dividing by 10 isn't the way, and counting zeros is incorrect. So the correct option is "By counting the number of places the decimal is moved."

For the number 560, non - zero digits (5 and 6) are significant. The trailing zero in a whole number without a decimal is ambiguous, but by the common rule for significant figures, trailing zeros in whole numbers without a decimal are not considered significant (unless specified otherwise). So 5 and 6 are significant, giving 2 significant figures.

Unit conversion (using conversion factors like \(\frac{1\ m}{100\ cm}\)) is used to change the unit of a measurement (e.g., from centimeters to meters) while keeping the actual value of the measurement the same. It doesn't increase precision, change the value, or reduce significant figures. So the correct option is "To change the unit of a measurement without changing its value."

Answer:

By counting the number of places the decimal is moved.

Question 8