Practice IB Physics Topic D.3 Motion in Electromagnetic Fields with authentic exam-style questions for both SL and HL students. This question bank focuses on the exact syllabus content for D.3 Motion in Electromagnetic Fields and mirrors Paper 1A, 1B, 2 style where relevant.
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An electron gun is used to produce a narrow beam of electrons which enters a region of uniform magnetic field. The electrons follow a circular path in this magnetic field.
State the direction of the force acting on an electron when it enters the magnetic field perpendicularly.
Write an equation for the magnetic force acting on a charged particle moving in a magnetic field.
Describe the path taken by the electron in the magnetic field and explain the cause of this motion.
Calculate the speed of an electron accelerated from rest through a potential difference of 4.0 kV.
Determine the radius of the circular path taken by the electron in a magnetic field of 0.30 T.
Suggest why a vacuum is necessary in the tube containing the electron beam.
In a laboratory experiment, singly ionized calcium ions (Ca⁺) of mass and charge are accelerated through a potential difference of 5.0 kV before entering a uniform magnetic field of strength . The magnetic field is perpendicular to the velocity of the ions.
Calculate the final speed of the calcium ions after acceleration.
Determine the radius of the path followed by the ions in the magnetic field.
Explain the effect on the radius if the same field is used with doubly ionized calcium ions ().
Suggest why mass spectrometers must be operated under low-pressure conditions.
Comment on the path shape if the ions entered the magnetic field at an angle other than to the field lines.
A wire of length carries a current of perpendicular to a uniform magnetic field of . If the wire is suspended horizontally and remains motionless, what is the minimum mass that the wire must have per unit length?
A charged particle moves at speed in a uniform magnetic field , entering at an angle to the field direction. What is the shape of its trajectory?
A beam of electrons travels in a region with perpendicular electric and magnetic fields. The electric field is and the magnetic field is . What is the speed of the electrons if they move undeflected?