Answer:
It is 8.1 × 10^-7
Step-by-step explanation:
[tex] {(9 \times {10}^{ - 4} )}^{2} \\ = \{{9}^{2} \times {10}^{( - 4 \times 2)} \} \\ = 81 \times {10}^{ - 8} \\ = 8.1 \times {10}^{ - 7} [/tex]
☆Concept:-
The Question is based on the law of exponents .
The law to be used in this question is
[tex]\boxed{\sf a^m\times a^n=a^{m+n}}[/tex]
Solution:-
[tex]\\ \tt\longmapsto (9\times 10^{-4})^2[/tex]
[tex]\\ \tt\longmapsto 9^2\times 10^{-4(2)}[/tex]
[tex]\\ \tt\longmapsto 81\times 10^{-8}[/tex]
[tex]\\ \tt\longmapsto 8.1\times 10^{-7}[/tex]
