What can you conclude about the major f scale from its name ?

The scale starts on F and ends on F, and has one flat in it, which is  B♭

changeable lenses of different focal lengths allow light to enter the camera, which then forms the image on light-sensitive film" is the one among the following statements about working principle behind a basic still camera is true.

soft,hard and rough for soft would be a pillow or a stuffed animal hard wood floor or a table rough paint