Find the value of $(-3{)}^4$.

If $a, m \mathrm{and} n$ are rational numbers, then $a^m\times a^n=a^p$. Then the value of $p=$_____.

When we add two numbers having the same base, we add the powers to get their sum.

There are three places $A,B,C$ as shown below. If distance between place $A$ and $B$is $\left(2.4\times {10}^6\right)$ $\mathrm{m}$ and distance between place $B$and $C$ is $(5.2\times {10}^5$) $\mathrm{m}$, then find the distance between place $A$ and $C$ in standard form.
 

A certain bacterium doubles itself every minute. If in a culture (a collection of bacteria), initially there are $3 \times {10}^5$ bacteria, how many bacteria will be present after $5$ minutes? Give your answer in standard form.

Express $345$ in the standard form.