1024, 64, 8, 2, 1, 1, 4
In each of these questions a number series is given. In each series only one number is wrong. Find out the wrong number.

The correct option is 4.

Let us analyze the given number series to find the underlying pattern. The series is:
1024, 64, 8, 2, 1, 1, 4

Let us examine the ratio of consecutive terms in the series starting from the first term:

$1024÷16=64$

$64÷8=8$

$8÷4=2$

$2÷2=1$

$1÷1=1$

Observe the divisors in each step:
16, 8, 4, 2, 1
Each divisor is divided by 2 to obtain the next divisor. Following this established pattern, the next divisor after 1 should be:

$1÷2=0.5$

Therefore, the next term in the series is calculated by dividing the current term (1) by the next divisor (0.5):

$1÷0.5=2$

However, the seventh term given in the series is 4 instead of 2. Thus, 4 is the wrong number in the series.