Yes, as a host employer, you are required to provide 32 hours or greater per week and time and half for any overtime worked.
For the most part all the interns are university students motivated to earn money working with a U.S. company and learn about the U.S. in general. In most cases, participants have borrowed money from family and friends in order to participate in the program and they expect to earn enough money to pay back this debt, cover the cost of living expenses, and hopefully take some money home at the end of their program.