Presentation on theme: "4-1 Radiant Energy. Waves Light travels in Waves similar to ocean waves Light waves are electromagnetic and consist of an electric and magnetic fields."— Presentation transcript:
Waves Light travels in Waves similar to ocean waves Light waves are electromagnetic and consist of an electric and magnetic fields oscillating at right angles to each other in the direction of motion.
Wavelength – distance between crests Amplitude – height of the wave measured from the origin to its crest or peak Brightness Frequency – tells how fast a wave oscillates The number of times a wave completes an up and down cycle Measured in cycles per second s -1 = 1/s = hertz = Hz
Light moves in space at a constant speed. c = 3.00 x 10 8 m/s Because of this, there is a relationship between wavelength and frequency. Shorter the wavelength, the faster the oscillation c = x = c/
Practice Problem Calculate the wavelength of a radio wave with a frequency of 93.1 x 10 6 s -1 = c/ = 3.00 x 10 8 m/s / 93.1 x 10 6 s -1 = 3.22 m
We see light in the visible spectrum Each color that we see has a different wavelengths. 400 nm (violet) – 700 nm ( red) Visible light is a very small portion of the electromagnetic spectrum. Much of the spectrum is below and above the Visible portion 10 -11 m – 10 1 m
Beyond red is the infrared portion. This is also called radiant heat Used in microwaves, radio waves, tv waves
Beyond violet is the ultraviolet radiation (UV) Responsible for sunburns and skin cancer. X-rays are even shorter in wavelength