Question

Study the given passage and answer the following question. Humans have been using numerous devices for the measurement of time since ancient times. Sundial, hour glass, water clock and candle clock were used to measure time. A sundial works on the principle that as the position of the Sun in the sky changes, so does the position and length of the shadow cast by an object. An hour glass uses sand to measure time. A water clock is also known as Clepsydra. A candle clock was an effective way to measure time indoors. Which of the following is INCORRECT about a sundial?​

Answer 1

Answer:

Is it a maths and what I can't understand