Question

1. why didn’t sundials work on cloudy days or at night?

a) they needed electricity
b) the gnomon broke
c) they required sunlight to make a shadow
d) people forgot how to read them

Explanation:

Sundials work by using the sun's rays to cast a shadow from the gnomon (the part that casts the shadow) onto the dial to tell time. On cloudy days, the sun is obscured, and at night, there is no sunlight. So, they need sunlight to create the shadow for time - telling. Option a is wrong because sundials don't use electricity. Option b is wrong as the gnomon breaking isn't related to cloudy nights or nights. Option d is wrong as people forgetting to read them isn't the reason they don't work in those conditions.

Answer:

c) They required sunlight to make a shadow