Question

(v) Sundials are
clocks
which work only when there is sun
in the sky.
(ancient/modern)​

Answer 1

Answer:

Ancient.

Explanation:

The earliest sundials known from the archaeological record are shadow clocks (1500 BC or BCE) from ancient Egyptian astronomy and Babylonian astronomy. Presumably, humans were telling time from shadow-lengths at an even earlier date, but this is hard to verify. In roughly 700 BC, the Old Testament describes a sundial—the "dial of Ahaz" mentioned in Isaiah 38:8 and 2 Kings 20:11. The people of Kush created sun dials through geometry.[4][5] The Roman writer Vitruvius lists dials and shadow clocks known at that time in his De architectura. A canonical sundial is one that indicates the canonical hours of liturgical acts. Such sundials were used from the 7th to the 14th centuries by the members of religious communities. The Italian astronomer Giovanni Padovani published a treatise on the sundial in 1570, in which he included instructions for the manufacture and laying out of mural (vertical) and horizontal sundials. Giuseppe Biancani's Constructio instrumenti ad horologia solaria (c. 1620) discusses how to make a perfect sundial. They have been commonly used since the 16th century.