Question

The least number having four digits which is a perfect square is:

• A. $1024$
• B. $1000$
• C. $1036$
• D. $1089$

Answer 1

The correct option is A $1024$

The given numbers are $1024,1000,1036,1089$.

The smallest number is $1000$ which contains $3$ zeros.

Therefore, it cannot be a square number.

Next smallest number is $1024$.

Now, $1024=2^{10}=(2^5{)}^2$ ....(after factorizing)

Therefore, $1024$ is a square number.