Electromagnetic oscillations & waves

Electromagnetic waves are produced by

• static charge

• An accelerated charge

• moving charge

• Charged particles

A real LC circuit

• Has zero resistance

• Has zero current

• Has a natural frequency

• Requires forced oscillations to work

Sound waves

• Are electromagnetic

• Are longitudinal

• Can not be reflected

• Can travel through a vacuum

Radio waves

• Are produced by the aerial

• Can pass through metal

• Can not be reflected

• Can only travel small distances

If a fully charged capacitor with initial charge Q is connected to a coil at the beginning of experiment. The time at which the energy is stored equally between the electric field and magnetic field is :

Frequency

• Is how fast something goes

• Is opposite to wavelength

• = wave speed x wave length

• Is measured in cycles per unit time

  
  

In electromagnetic waves the phase difference between electric field vector and magnetic field vector is

• zero

• π/2

• π

• π/3

Which of the following rays are not electromagnetic waves?

• Gamma rays

• Alfa rays

• Heat rays

• X rays

• capacitance

• capacitor

• inductance

• inductor

This is a picture of a simple electromagnet. How can the electromagnet be made stronger?

• Add more coils of wire to the nail.

• Use a smaller battery.

• Reverse the poles of the magnet.

• Remove all the coils and the nail.