How does the length of shadow change from morning to evening at any place?
As the angle between two plane mirrors is decreased gradually, the number of images of an object placed between them:
(a) increases gradually
(b) decreases gradually
(c) first increases then decreases
(d) first decreases then increases
When the pitch of note produced by a harmonium is lowered, then the wavelength of the note :
(a) decreases
(b) first decreases and then increases
(c) increases
(d) remains the same