Resultaten

When electromagnetic radiation is absorbed by a material the energy it carries has to go somewhere. When lower energy waves, like radio and infrared waves, are absorbed there can be an increase in temperature of the absorbing material. Higher energy waves, like x-ray and gamma waves, can actually permanently damage or change materials. Learn about the different types of electromagnetic waves and how their energies can influence their effects on objects.

The idea of the electric field, how it's useful, and explains how the electric field is defined.

There are many different processes and phenomena that emit electromagnetic radiation. Humans have taken advantage of many of these processes to develop technologies that use electromagnetic radiation.

The beauty of a coral reef, the warm radiance of sunshine, the sting of sunburn, the X-ray revealing a broken bone, even microwave popcorn—all are brought to us by electromagnetic waves. The list of the various types of electromagnetic waves, ranging from radio transmission waves to nuclear gamma-ray (γ-ray) emissions, is interesting in itself.

Even more intriguing is that all of these different phenomena are manifestations of the same thing—electromagnetic waves (see Figure 15.1). What are electromagnetic waves? How are they created, and how do they travel? How can we understand their widely varying properties? What is the relationship between electric and magnetic effects? These and other questions will be explored.

Forces at a distance are explained by fields (gravitational, electric, and magnetic) permeating space that can transfer energy through space. Magnets or electric currents cause magnetic fields; electric charges or changing magnetic fields cause electric fields.

Magnetism is an interaction that allows certain kinds of objects, which are called ‘magnetic’ objects, to exert forces on each other without physically touching. A magnetic object is surrounded by a magnetic ‘field’ that gets weaker as one moves further away from the object. A second object can feel a magnetic force from the first object because it feels the magnetic field of the first object. The further away the objects are the weaker the magnetic force will be.

Photoelectric materials emit electrons when they absorb light of a high-enough frequency.

An explanation of wave interference and solution of a few examples to find the value of the total wave when two wave pulses overlap

The wavelength and frequency of a wave are related to one another by the speed of travel of the wave, which depends on the type of wave and the medium through which it is passing.

• Make waves with water, sound, and light and see how they are related.
• Discuss wave properties using common vocabulary.
• Explain how changing the frequency and amplitude affects the characteristics of the wave.
• Design an experiment to measure the speed of the wave.