Sonam went on the roof of her house with a firki and noticed that her firki starts rotating. What is/are the reason(s)? (a) Beacause the side of the firki facing the sun gets hotter and hence becomes lighter which causes it to rotate (b) Because the force of air was rotating the firki (c) Because the structure of a firki is such that it is not alligned with its central rotational axis which causes it to keep on rotating