Physics OBJ:

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11-20: DADBCBBCAA

21-30: EECACCBABC

31-40: BDBDDCBAAA

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51-60: CBCCDECCEA

4a)Whenever light passes from one material into another, it changes speeds and bends. You’ve probably noticed this before whenever you try to look at something underwater. Imagine that you look down into a clear lake and see a fish under the water.

4b) 1. Greater Bandwidth

Copper cables were originally designed for voice transmission and have a limited bandwidth. 

2. Faster Speeds

Fiber optic cables have a core that carries light to transmit data. This allows fiber optic cables to carry signals at speeds that are only about 31 percent slower than the speed of light—faster than Cat5 or Cat6 copper cables. 

3. Longer Distances

Fiber optic cables can carry signals much farther than the typical 328-foot limitation for copper cables. 

4. Better Reliability

Fiber is immune to temperature changes, severe weather and moisture, all of which can hamper the connectivity of copper cable. Plus, fiber does not carry electric current, so it’s not bothered by electromagnetic interference (EMI) that can interrupt data transmission.