Refers to the lottery system or event itself, not a physical ticket.
Many people buy the year-end jumbo lottery every year.
宝くじで一億円当たったら、何をしますか。
What would you do if you won 100 million yen in the lottery?
Refers to the physical ticket itself.
宝くじを10枚買った。
I bought ten lottery tickets.
当選した宝くじを銀行に持っていく。
I take the winning lottery ticket to the bank.
I bought a lottery ticket at the stand in front of the station.
If I win the lottery, I want to buy a house.
My lottery ticket didn't win again this year.
I heard someone won 100 million yen in the lottery.
The lottery drawing is held every week.