Answer
The given sequence is geometric sequence and the common ratio = 2.
Work Step by Step
The given general term is $a_{n}$ = $2^{n}$
First term $a_{1}$ = 2 (if n=1)
Second term $a_{2}$ = 4 (if n=2)
Third term $a_{3}$ = 8 (if n=3)
Forth term $a_{4}$ = 16 (if n=4)
Ratio of consecutive terms.
$\frac{16}{8}$ = 2.
$\frac{8}{4}$ = 2.
$\frac{4}{2}$ = 2.
From above we observe that the ratio of two consecutive terms is constant. So the given sequence is geometric sequence and the common ratio = 2.