The result after adding `3.8xx10^(-6)` and `4.2xx10^(-5)` with due regards to significant figures is

Options

A. `4.58 xx 10^(-5)`
B. `4.6 xx 10^(-5)`
C. `4.5 xx 10^(-5)`
D. `4.7 xx 10^(-5)`

Answer

B

Explanation

We will use the general rule of addition by making the powers same.
i.e. we will add `3.8 xx 10^(-6)` and `4.2 xx 10^(-6)` we get `= 45.8 xx 10^(-6)= 4.58 xx 10^(-5)`
As least number of significant figures in given values are 2 so we round off the result to `4.6 xx 10^(-5)`