Answer: When you turn a light on it becomes bright :)
In electrical wiring, a light switch is a switch most commonly used to operate electric lights, permanently connected equipment, or electrical outlets. Portable lamps such as table lamps may have a light switch mounted on the socket, base, or in-line with the cord. Manually operated on/off switches may be substituted by dimmer switches that allow controlling the brightness of lamps as well as turning them on or off, time-controlled switches, occupancy-sensing switches, and remotely controlled switches and dimmers. Light switches are also found in flashlights, vehicles, and other devices.
It is c) the energy that does work through chemical reactions
The atomic number of calcium is 20 which means it has 20 protons and as an atom (not an ion) it also has 20 electrons. These are in four energy levels (1 though 4) .
Depends if the reaction is endo or exo thermic
Endothermic reaction
Increasing the temperature will shift the equilibrium to the right-hand side of the equilibrium. to oppose the change in temperature.
Exothermic reaction
Increasing the temperature will shift the equilibrium to the left-hand side of the equilibrium. to oppose the change in temperature.
Hope that helps