science

• What are the components needed to make an electromagnet?

  • Iron core (usually a nail)
  • Coil of wire wound around the core
  • Battery to provide electrical current
• What is the third essential component of an electromagnet?

  Battery
• If the current flowing through the solenoid in part (a) is increased, what would happen to the force exerted on the plunger?


  The force on the plunger would increase
• How does current strength affect magnetic field strength?


  Higher current produces a stronger magnetic field
• What connects to the ends of the wire in an electromagnet?

  Battery
• What is the magnetic field strength with 10 windings?

  Weak
• How is an electromagnet created?

  By flowing electric current through a coiled wire
• What are the key components of an electromagnet?

  • Coiled wire
  • Iron nail
  • Battery
• What is the first essential component of an electromagnet?

  Iron core
• What is the role of the core material in an electromagnet?

  It enhances the magnetic field strength
• What are the levels of current strength and their corresponding magnetic field strengths?

  • Low current: Weak magnetic field
  • Moderate current: Medium magnetic field
  • High current: Strong magnetic field
• What is the name of the component labeled 1 in the image?

  electromagnetic coil - soft iron core
• What happens to an electromagnet when the electric current is turned off?

  It loses its magnetic properties
• What is an electromagnet?

  A magnet created by electric current
• How can the magnetic field strength in part (b) be increased?

  • Increase the current flowing through the coils
  • Use more turns of wire in the coils
  • Use a material with higher magnetic permeability for the core
• What is the main component of the electromagnet?

  Coiled wire
• What is the name of the device shown in the image?

  Simple electromagnet
• How do electromagnets differ from permanent magnets?

  Electromagnets are temporary and require current
• What is the relationship between electric current and magnetic fields?

  Electric current generates a magnetic field
• What happens to the magnetic field lines when many loops of wire are coiled together?

  • The field lines concentrate inside the coil
  • This occurs in a solenoid
• How do the formulas for air core and iron core differ?

  The iron core formula includes a permeability constant 'k'
• What do the red arrows in the image represent?

  The magnetic field lines
• What is the name of the component labeled 3 in the image?

  soft iron armature
• How can you create a strong electromagnet using a nail?

  Wrap a wire around the nail and run electricity
• What do the labels "I_in" and "I_out" represent in part (b)?

  The input and output currents of the device
• How does the magnetic field in part (b) work?

  • The magnetic field is created by the flow of current through the coils (shown as N and S)
  • The magnetic field lines flow from the north pole to the south pole
  • The magnetic field interacts with the magnetic domains in the iron core, causing it to magnetize
• How does the solenoid in part (a) work?

  When current flows through the coil, it creates a magnetic field that can move the plunger in and out
• What is the magnetic field strength with 100 windings?

  Strong
• How many windings are needed for a strong magnetic field?

  100 windings
• What should you do after pointing your thumb in the direction of the current?

  Curl your fingers around the wire
• How do the contacts (labeled 4) work with the relay (labeled 2)?

  • The contacts are part of the relay
  • When the relay is activated, the contacts close to complete the circuit
  • This allows the current to flow from the input circuit to the output circuit and power the electric motor
• What is the magnetic field strength with 50 windings?

  Medium
• How do the magnetic field lines in part (b) differ from the magnetic field of a bar magnet?


  The magnetic field lines in part (b) are more complex and concentrated within the iron core, unlike the simple dipole field of a bar magnet
• What is the formula for the magnetic field of an iron core solenoid?

  $B =$$k \mu_0 n I$
• What is the formula for magnetic field strength in an iron core?

  $B =$$k \mu_{0} n I$
• How does inserting an iron core affect the magnetic field of a solenoid?

  • Inserting an iron core increases the magnetic field of the solenoid by a factor of k, where k is the permeability of the iron core.
  • This is because the iron core has a higher magnetic permeability than air, allowing more magnetic flux to be generated.
• How can you find the direction of the magnetic field created by an electric current?

  Point your thumb in the current's direction
• What happens when the input current activates the electromagnet in a relay?

  It pulls the armature to close contacts
• What is the effect of an air core on magnetic field strength?

  It results in much weaker magnetic fields
• What property describes how easily a magnetic field can form?

  Magnetic permeability