question_answer

There are 10 lamps in a hall. Each one of them can be switched on independently. Find the number of ways in which hall can be illuminated.

A)  \[{{2}^{10}}-2\]         

B)  \[{{2}^{10}}-1~\]

C)  \[{{2}^{10}}\text{+ }1~\]                 

D)  None of these