Question

An old-fashioned incandescent light bulb rated at 60 W might have the same brightness as a compact fluorescent bulb that is rated at only 14 W. How is this possible? (Hint: think about what happens when the bulbs are left on for a very long time and about other ways energy can get used.)

Answer 1

In an old-fashioned incandescent bulb, the large portion of consumed energy is radiated in the form of heat (infrared region) which we can not see with naked eye, but we can feel that old fashioned bulb produce more heat than modern compact fluorescent bulb.

One can say that modern bulb have higher efficiency as they convert major part of consumed electric energy into light energy in the visible region of electromagnetic spectrum.

Most of the energy is lost in the form of heat (Joule's Heat)