How are the two plane mirrors in a periscope arranged:

(a) with respect to one another?

(b) with respect to sides of the tube?

Name the phenomenon responsible for the following effect:

When we sit in front of a plane mirror and write with our right hand, it appears in the mirror that we are writing with the left hand.

Name a device which works on the reflection of reflected light.

What will be the number of images formed when an object is placed between two parallel plane mirrors facing each other?

Name an instrument or toy which works by producing multiple reflections from three plane mirrors to form beautiful patterns.