Why does light change path when it changes mediums

Under what conditions will an object experience a gravitational force? Under what conditions will an object experience an electric force? Under what conditions will an object experience a magnetic force?

In a fluorescent tube of diameter 3 cm, 3 times 1018 electrons and 0.75 times 1018 positive ions (with a charge of + e) flow through a cross-sectional area each second. What is the current in the tube?

Object a has less thermal energy than object b, but heat flows from object a to object b. what conditions would make it possible?

A rectangular trough, 1.6 m long, 0.50 m wide, and 0.45 m deep, is completely full of water. One end of the trough has a small drain plug right at the bottom edge. Part A When you pull the plug, at what speed does water emerge from the hole

What is the equation to find the volume of a hemisphere? I know the equation to get the volume of a sphere. It's 4/3 pi R cubed?

A train is moving 4.82 m/s when it begins to accelerate. After 24.8s it is moving 7.09m/s how far did it move in that time

List three different emotions?

The jet stream flows from east to west across the United States. True False

You are in a hot air balloon, 350 m above the flat Texas plains. You look out toward the horizon. How far out can you see--that is, how far is your horizon? The Earth's radius is about 6400 km.

You and your housemate have an argument over the cost of the electric bill. You want to turn off the outside porch light before going to bed each night.