In an light bulb what energy produces thermal energy which then produces radiant energy?

Answer 1

When the lightbulb is placed in a bulb holder, a voltage is applied across the metallic filament. As a result, a current of electrons now flows from through the filament. As the electrons flow through the metallic filament, they collide with the atoms in the filament, causing the atoms to vibrate. This vibration is what causes the temperature of the filament to rise.

When the temperature of an object increases, it will always radiate thermal energy via black body radiation. A more intuitive explanation, is that the atoms in the object vibrate faster and faster as a function of temperature. As a result, the charges around the atoms will vibrate. When charges accelerate and decelerate, they induce an electromagnetic wave, or what is commonly known as light, which radiates away from the atoms.

The wavelength of the light that is emitted from the atoms depends on the vibration of the atoms, or equivalently the temperature of the material. So the faster the vibrations, the higher the frequencies and amplitudes (intensity) of the light.

The question is misleading in that it implies that light and thermal energy are two different forms of energy. In fact, light and thermal energy are the exact same thing, but just at different wavelengths. The light that we see in our eyes corresponds to wavelengths in the visible spectrum (450nm - 650nm), whereas thermal radiated energy is at longer wavelengths (infrared).

Therefore, when the filament is heated up, the atoms vibrate, which causes light to be emitted over a large spectrum of wavelengths, some of that is visible light and some of that is infrared light (heat). This is how a lightbulb can generate both "light" and "thermal energy."

Answer 2

In incandescent bulbs, when electricity passes through a tungsten filament, the filament provides resistance to the flow of current, resulting in that filament heating up as it is one of the properties of electrical resistance. This heating of the element excites atoms in the filament and causes them to in effect, break off from the filament. This causes them to interact with other atoms in the gases inside the glass bulb. This causes the gas inside the bulb to increase in energy, which results in numerous impacts against the inside of the bulb and through these impacts heat is generated in the glass bulb.

Answer 3

the energy that produces heat in a light bulb is electromagnetic.

Answer 4

In a light bulb, electrical energy is converted to thermal energy when the filament heats up. This thermal energy causes the filament to emit radiant energy in the form of light.