Doors Windows and Staircases Questions and Answers

Answer: B

It is incorrect that collapsible doors revolve about a pivoted point. Revolving doors rotate about a central pivot, but a collapsible door is made of steel strips or channels joined in a lattice so that it folds or collapses sideways, like a concertina, and slides in a track. The other three statements fit: the open lattice gives no privacy to a room, the gaps let air-conditioned air escape so they are not suitable for air-conditioned halls, and they are used as an entry and exit gate for shops and garages.

Answer: C

The wooden plank or slab of concrete or stone usually laid at the bottom of an entrance doorway is called the threshold, which forms the base of the door opening. A shutter is the movable leaf of the door, the door frame is the fixed assembly of posts and horizontal members that holds the shutter, and the reveal is the vertical side surface of the wall opening, left exposed where the frame is set back. None of those is the member laid at the bottom.