basic circuit and energy?

Question

what conversion does the electrical energy forcing its way through a (light)bulb go through? is the energy used up?



if you had 2 motors to wire and you wanted them to run at full power and not burn up, how would you wire them?

Answer 1

The light-bulb has a tungsten filament, which has electrical resistance. The voltage applied across the resistance causes a current to flow. The value of the current is: I = V/R, where I is the current in amps, V is the voltage in volts, and R is the resistance in ohms. The current flowing through the resistance causes it to heat up--it dissipates power. The power is: P = I*V, or P = R*I^2, where the power is in watts. MOST of that power produces heat; in an incandescent bulb only a little goes into light. Power, incidentally, is energy per unit time. Watts are Joules/sec, where the joule is the SI standard unit of energy.

As for the motors, connect them in parallel. They will each receive the same voltage, and each will draw the amount of current it needs.

Answer 2

A light bulb is a resistor. When the current tries to move in the resistor it encounters what can be thought of as friction. When somehing tries to move against a frictional force, much of the energy is converted to heat. So in a circuit with a lightbulb, most of the energy is turned into heat and leaves the circuit. Some of that energy of course goes into visible light as well.

Power = current * voltage or power = (current)^2 * resistance

In a parallel circuit the voltage is the same across the two branches. In a series circuit, the current is the same through the whole circuit.

If we assume the motors have a resistance, resistors in series add so two motors in series will get hotter than two motors in parallel. I'd wire the the motors in parallel. If they are identical they'd both run at the same power with the same current and the resistance of the circuit would decrease.

Answer 3

1. The energy is converted from electrical to broad spectrum electromagnetic radiation (light & heat). The power radiated is equal to the power delivered.

2. I would wire each motor through a motor starter and fused disconnect to its rated supply voltage.

Answer 4

Imagine trying to cram a thousand fat people down a narrow hallway through a single revolving door in a hurry. This is what happens to electrons in a lightbulb.

The lightbulb wire is so thin that the amount of electricity being pushed through causes the electrons to heat up - much like a pile of fat people in a confined space. The wires in your walls are thick enough to allow sufficient electricity through without heating up.