​How many terms are there in 2, 4, 8, 16, ..., 1024?

Correct option is D

Given:

Sequence: 2, 4, 8, 16, ..., 1024

Formula Used: 

Geometric Progression 

​$$T_n = a \times r^{n-1}$$ 

where, common ratio r = $$\frac{\text{second term}}{\text{first term}}$$​​

Solution:

2, 4, 8, 16, ..., 1024

This is a Geometric Progression (G.P.) with:

First term a = 2

Common ratio r = 2

Last term $$T_n$$​ = 1024 

Now, Using the formula;

​$$1024 = 2 \times 2^{n-1}\\ \ \\ 1024 = 2^1 \times 2^{n-1} = 2^n\\ \ \\ 2^n = 1024\\ \ \\ 2^n = 2^{10}$$

Now,  comparing 

n = 10 

Thus, total term are 10