Electromagnetic Force
Problems
practice
- Write something.
- Write something.
- Write something.
- Write something completely different.
conceptual
- How does the direction of a magnetic force on a moving charged particle differ from the direction of an electric force? State the direction of each force relative to the respective field.
- Describe the path of a charged particle in a uniform magnetic field if its velocity is…
- parallel to the magnetic field
- perpendicular to the magnetic field
- at an angle to the magnetic field that is neither parallel nor perpendicular
- This is an experiment that you can try at home if you have an old TV or computer monitor. Take a strong magnet and hold it up to a CRT display.
- Why does the image become distorted?
- Why is the image covered with colored bands of red, green, and blue?
- Why does the color stay screwed up after the magnet is removed?
- Why does the color return to normal after the television has been turned off and back on?
- Why doesn't this effect occur with LED, LCD, and plasma displays?
- Show the direction of the force acting on the current carrying wire between the two bar magnets.
- Determine the direction of the force acting on the electron moving between the poles of a horseshoe magnet.
- The tracks highlighted in the photograph on the right were made by subatomic particles in a collider. The tracks highlighted in red and green were made by electrons.
- How are the tracks made by the electrons different from the other tracks? Why are they different?
- How is the track highlighted in red different from the track highlighted in green? Why is it different?
- A positively charged particle is placed at rest in a region of uniform electric and magnetic fields. Describe…
- the direction of the electric and magnetic forces just before the particle starts moving
- the resulting path of the charge
if the two fields are…
- parallel
- antiparallel
- perpendicular
numerical
- Three successive electromagnetic experiments are performed on an electron beam as shown in the diagram below. (Ignore the effects of gravity in this problem.)
- The beam enters region a with negligible initial velocity and is accelerated across a potential difference of 10,000 V in a distance of 10 cm. Determine…
- the magnitude of the electric field in this region
- the net force on the electrons in this region
- the final speed of the electrons when they exit this region
- The beam then passes into region b where there are both electric and magnetic fields. The electric field strength in region b has the same magnitude as region a but points downward. The magnetic field points inward and is adjusted so that the magnetic and electric forces on the electron beam cancel. Determine…
- the magnitude of the magnetic field in this region
- The beam finally enters region c, where there is a magnetic field but no electric field. The electrons follow a semicircular path with a radius of 7.5 cm. Determine…
- the magnitude and direction of the magnetic field in this region
- The beam enters region a with negligible initial velocity and is accelerated across a potential difference of 10,000 V in a distance of 10 cm. Determine…
algebraic
- Three problems about electromagnetic units…
- Show that the units in this expression (μ0 = 4π × 10−7 T m/A) are equivalent to the units in this expression (μ0 = 4π × 10−7 N/A2) for the permeability of free space.
- Express the permeability of free space in terms of funamental units.
- Reduce the tesla to its equivalent in SI base units.