Can you help me with these? I am struggling

Snell's Law Assignment 1) You measure the critical angle of a crystal to be 37.6 when the crystal is in air. You submerge the crystal in an unknown liquid and measure a new critical angle of 63.8. What is the index of refraction for the unknown liquid? 2) A block of unknown material is submerged in water. Light in the water is incident on the block at an angle of 310. The angle of refraction in the block is 270. What is the index of refraction of the unknown material? 3) A light source is located 1.55m below the surface of a swimming pool and 0.545m from one edge of the pool. At what angle does the light reaching the edge of the pool leave the water and does this cause the light to be viewed as deeper or shallower than it actually is? 4) A ray of light is incident upon an equilateral triangular glass prism, n=1.5. If the angle of incident is 7.5 at the mid-point of one side, determine the angle at which light leaves the prism. 5) You have a converging lens (bulges out on both sides) with a focal length of 5.0cm. If you place an object 4.0cm from the lens that is 2.0cm tall: a. Draw a sketch (doesn't need to be to scale) of the situation; b. Determine the image distance; c. Determine the image height; d. Describe the image; e. Determine the magnification