Why does spring tides occur

Because the Moon and the Sun are along the same line with the Earth

Explanation:

Tides are phenomenon that occur periodically on Earth. The term "tides" refer to the increase/decrease in the sea level in oceans and seas due to the combined effect of the gravitational force of the Moon and of the Sun on the water on Earth. In fact, the Moon (and the Sun also) exerts an attractive gravitational force on the water in the oceans, causing the sea level to rise when the Moon is facing that portion of water.

In particular, two types of tides are possible:

- Spring tides: these occurs when the Moon and the Sun are along the same line. In this situation, the gravitational forces exerted by the Moon and the Sun on the water act along the same line, so the combined effect is to increase the amount of tide, so the sea level rises more.

- Neap tides: these occurs when the Moon and the Sun are at 90 degrees from each other, with respect to the Earth. As a result, the gravitational force exerted by the Moon and the Sun on the water act perpendicular to each other, so the combined effect of the tide on the water is less than the spring tides, so the sea level is lower than the spring tides.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current