Perform the calculation and record the answer with the correct number of significant figures.

0.05

Explanation:

In addition and subtraction operations such as this, the final result is reported in the least number of significant figures. For this question, we round up the answer to the least number of places to the decimal point, which is 1 as in 6.5

In this question, (6.5-6.28)/4.71

= 0.22/4.71

= 0.046709

The least number of significant figures in the question is 2 s.f i.e. 6.5, which has 1 number of places to the decimal point.

Hence, we round up 0.046709 to 1 number of places to the decimal point

= 0.05

Note that, the zero before the first non-zero digit (5) is insignificant. Hence, 0.05 is in the least number of places to the decimal point (1)

beta decay is the answer