Photo booth not working

I can't use my photo booth on my MacBook Air 13. Camera works fine on zoom and FaceTime but photo booth shows boank screeen although green light is on along with camera sign. I tried to force quit but photo booth doesn't appear in that folder. It only shows preview and finder. I also can't duplicate it by right clicking. I am new user. Please guide me. I need to use photo booth very badly . Thank you everyone..