While watering a distant plant, a gardener partially closes the exit hole of the pipe by putting his finger on it. Explain why this results in the water stream going to a larger distance.

A beaker is placed on the top of a coin. The top of the beaker is closed with an opaque body with a small hole. View the coin from an angle , slowly add water through the hole while continuing to view the coin from the same angle. Repeat the procedure using cooking oil. a. What happens when water is continuously added ? b. What about the heights of water and oil, when con completely disappears ? c. In which liquid, the coin is concealed best with minimum height? Why? d. What is the valation between opitieal angle and refrective index. ?