At the end of your interview, the consular officer will inform you whether your visa application is approved or denied.
Some visa applications require further administrative processing, which takes additional time after the interview. Applicants are advised of this requirement when they apply. When administrative processing is required, the timing will vary based on the individual circumstances of each case. You can check the status of your visa application on ceac.state.gov.
If your visa has been denied, you may find useful information on Ineligibilities and Waivers on travel.state.gov.