• Question: 1. Why is it that the neutron in a nucleus of an atom does not have charges? 2. Are there ways of making solar powered vehicles to reduce pollution?

    Asked by Fridaus to Jelili, Noel, Robinson, Shilla, Simon on 23 May 2018.
    • Photo: Shillah Simiyu

      Shillah Simiyu answered on 23 May 2018:

      1. To answer question 1, lets start from the basics. The atom is made up of protons, neutrons and electrons. Initially, it was thought that protons, neutrons and electrons were fundamental particles. Fundamental particles cannot be broken down into smaller particles. However,after the invention of the particles accelerator, it was discovered that only electrons are fundamental particles, while protons are neutrons are not.The particle accelerator aka atom smasher, whose main use is to study particle physics showed that neutrons and protons are made up of tiny particles called quarks. An “up” quark has a charge of +2/3 while a “down” or “bottom” quark has a charge of -1/3.

      A proton is composed of 3 quarks: two up quarks and one down quark. The total charge of a protons therefore is 2(+2/3)+(-1/3)=+1 which explains why the overall charge of a proton is +1. A neutron on the other side is composed of one up quark and two down quarks. Hence the charge of a neutron is (+2/3)+2(-1/3)=0 giving it no overall charge, hence Neutral.

      2. Solar cars depend on a solar array that uses photovoltaic cells (PV cells) to convert sunlight into electricity. When sunlight (photons) strike PV cells, they excite electrons and allow them to flow, creating an electric current, to drive electric motors which then move the car. PV cells are made of semiconductor materials such as silicon and alloys of indium, gallium and nitrogen. Crystalline silicon is the most common material used and has an efficiency rate of 15-20%. In addition to solar PV cells and basic equipment, solar-powered cars often also feature battery packs to store generated electricity, and thereby allow travel even when the sun isn’t out (or the sunlight isn’t very strong).
      There are some limitations inherent in the design of solar-powered cars, such as space limitations on the surface and roof of a vehicle for solar cells (and thus energy limitations, and range limitations); and also limited capacity to carry heavy batteries (thus energy storage limitations as well, and range limitations). The weight of solar PV cells is another limiting factor.

      While these limitations may be lessened to some degree or other over the coming years as a result of falling battery and solar cell costs, they will likely always remain as important factors to consider when determining the practicality of a solar-powered car. As a result, in most circumstances, an electric car paired with a ground- or roof-mounted solar PV array is likely to be far more practical and economical. Improvements in research, engineering and design of the solar car might however mean that we might just have a solar powered car in the market in the near future.A few prototypes have already been made.