In the set-builder notation (rule method),the null set is represented by:

Make correct statements by filling in the symbols $\subset$ or $\not\subset$ in the blank spaces:
$\{ x:x \text{ is a student of class } XI \text{ of your school} \} \dots \{ x:x \text{ is a student of your school} \}$

If $Q = \{x : x = \frac{1}{y}, y \in N\}$,then which of the following is true?

Let $A = \{1, 2, 3, 4, 5, 6\}$. Insert the appropriate symbol $\in$ or $\notin$ in the blank space:
$10 \dots A$

Find the union of each of the following pairs of sets:
$A = \{1, 2, 3\}, B = \varnothing$

If $A = \{ \phi, \{ \phi \} \}$,then the power set of set $A$ is: