Electromagnitism II

• An electric field is a scalar quantity - False (Vector quantity)
• Magnetism is a phenomenon that arises only from the movement of electric charges
• A magnetic field is not always generated by a permanent magnet - (Electromagnet)
• Magnetic flux is a measure of the strength of a magnetic field
• Direct current does not periodically reverse its direction of flow
• Ohm's law creates voltage, current, and resistance

  Formulas:

  V= IxR

  R= V/I

  I= V/R
• Resistance is not the measure of how easily current can flow through a material - False (Through a conductor)
• Electrical power is measured in amperes

  
  

  Power = Watts

  Current= Amperes

  Resistance= Ohm
• Electromagnetic induction is the process of generating a magnetic field by passing a current through a conductor
• A transformer does not change the frequency of an alternating current
• In a circuit, current does not flow from low potential to high potential - (High to Low)
• The frequency of an AC signal is the number of complete cycles in one second
• MRI uses magnetic field and radio waves to create images of the body
• MRI can image both bones/hard tissues and soft tissues/organs
• MRI stands for Magnetic Resonance Imaging
• MRI machines use strong magnetic fields which affect metal objects inside the body
• MRI scans are slower than CT scans
• MRI scans do not use ionizing radiation to create images

  
  

  Ultrasound - Sound waves

  MRI - Radio waves

  Chemotherapy - Ionizing radiation
• MRI scans are not always performed in a standing position - False
• MRI scans do not provide real time imaging of the body's internal structure - (Static, not real time)
• MRI scans do not require the patient to hold their breath during the procedure
• DC stands for Direct Current
• Alternating Current can change direction periodically
• Batteries do not provide AC power - (DC power)
• The voltage of DC remains constant over time
• The voltage of AC changes polarity periodically - (Since it is a sine wave, the polarity means positive and negative)
• Power transmission over long distances is not more efficient with DC than AC - (In long distances, it is more efficient to use AC)
• AC is easier to convert to higher or lower voltages using a transformer
• The frequency of AC is measured in Hertz(Hz)
• AC cannot be easily stored in batteries
• Electrostatic deals with the study of stationary electric charge
• Static electricity is not the result of moving electric charges
• The law of conservation of charge states that electric charge cannot be created or destroyed
• Coulomb's law describes the relationship between electric charges and the force between them
• Electric field lines point away from positive charges and towards negative charges

  
• Conductors allow electric charges to move freely within them - Conductors can't conduct readily
• Lightning is an example of a discharge of static electricity
• The electric field inside a conductor is not always zero - It can become zero when it reaches equilibrium.
• Van de Graaff generator is a device used to produce high voltage static electricity
• The unit of electric potential is Volts