Question 1

  1. coal → steam → water

  2. When water molecules gain kinetic energy, they start moving faster and the temperature rises. This allows them to break intermolecular bonds and turn into steam.

  3. When phase change is occurring from water to steam, the energy absorbed is used to break the intermolecular forces rather than increase temperature and speed.

  4. E = (2.5 x 10^7) x (4.5 x 10^5)

    = 1.125 x 10^13

  5. 0.28 = Useful O/P / 2.67 x 10^10

    Useful O/P = (2.67 x 10^10) x 0.28

    = 7.476 x 10^9

  6. heat absorbed and re-emitted by greenhouse gases

  7. Trapping heat energy in the earth’s atmosphere would cause more extreme weather events because greenhouse gases absorb and re-emit the heat back into the atmosphere, increasing global temperatures. This results in the melting of ice in glaciers as increased heat increases the rate of evaporation leading to rising sea levels and floodings.

Question 2

  1. p = 92

    n = 143

  2. The protons of the daughter nuclei add up to the number of protons in the parent nucleus. Two neutrons are released in the reaction but the number of protons and neutrons is the same before and after the reaction.

  3. Chain reaction means that a reaction results in another one. In this reaction, the free neutrons released cause another reaction to occur.

  4. An uncontrolled chain reaction in a power plant is very dangerous because they can quickly escalate. If too much energy is released, it may result in a nuclear meltdown. This can lead to the emission of radioactive material into the surrounding environment.

  5. 1500 million years

  6. It poses a significant change because it needs appropriate, safe storage even after its disposal. It is also radioactive which is harmful to human health.

Question 3

  1. How does the length of the wire affect its resistance?
  2. If the length increases, then the resistance will also increase because the formula states: R = pL/A, showing that resistance and length have a proportional relationship. This is because as the length increases, the electrons have more obstacles to overcome and therefore face more resistance.
  3. silver all
  4. The selection that I made had 6 increments of length and the material and csa were constant. This is important because we only have 2 IV so we can have a fair test.