Questions

The size of the pupil of the eye automatically adjusts itself  according to the intensity of light passing through it;if the intensity is more , the size is less, if less, it is more. So in our case the pupil should dilate i.e, increase in size to be able to see in the dark . This switchover takes sometime. But here the entry into the dark room is immediate . So the eye has no time to adjust itself and hence is not able to see at all for a while.

Lewis Edson Waterman patented the first practical fountain pen in 1884.

As clear from the diagram, AD2=122+92=152

 So, AD = 15

Word length refers to the number of bits processed by a computer's CPU in one go. These days, typically 32 bits or 64 bits are used.

Data bus size, instruction size, address size are usually multiples of the word size.