Magnetic resonance (MR) scanner (AQA A-Level Physics): Quizzes
📚Quizzes
Practise the questions
10 questions from this quiz
ShowHide
Practise the questions
10 questions from this quiz
What type of magnet is used in an MRI scanner?
What type of magnet is used in an MRI scanner?
Superconducting magnet
What substance is used to cool the magnet in an MRI scanner?
What substance is used to cool the magnet in an MRI scanner?
Liquid helium
Which particles in the body are primarily responsible for MRI imaging?
Which particles in the body are primarily responsible for MRI imaging?
Protons (hydrogen nuclei)
Why do protons behave like tiny magnets in an MRI scanner?
Why do protons behave like tiny magnets in an MRI scanner?
Due to their intrinsic spin
Why do most protons align parallel to the magnetic field rather than antiparallel?
Why do most protons align parallel to the magnetic field rather than antiparallel?
Parallel alignment is lower in energy
What motion do protons undergo around the magnetic field lines in an MRI scanner?
What motion do protons undergo around the magnetic field lines in an MRI scanner?
Precession
What is the function of gradient coils in an MRI scanner?
What is the function of gradient coils in an MRI scanner?
Vary magnetic field strength across body
What do RF pulses do to protons in an MRI scanner?
What do RF pulses do to protons in an MRI scanner?
Excite them and flip them out of alignment
How is the contrast in MRI images adjusted?
How is the contrast in MRI images adjusted?
By modifying time between RF pulses
Why are MRI scanners not suitable for patients with certain metal implants?
Why are MRI scanners not suitable for patients with certain metal implants?
Due to the strong magnetic field