Question (a)
In which direction, relative to the coordinate system shown, should the magnetic field point for the positive ions to move along the path shown by the dashed line in the diagram?
Answer (a)
We use the right hand rule.
points towards the center of the arc and points downwards initially. So, points into the page.
Question (b)
Should plate K have a positive or negative voltage polarity with respect to plate L?
Answer (b)
In the initial vertical section, the velocity
is downwards and is into the page (from the prev problem). Using right hand rule, we know that will point to the right. In order to counteract that effect and keep the velocity downwards, The Electric Field needs to point to the left. Therefore, Plate
should have negative voltage ( points from high to low Electric Potential Difference)
Question (c)
Calculate the magnitude of the electric field between the two plates.
Answer (c)
Question (d)
Calculate the speed of the particle that can pass through the plates without being deflected.
Answer (d)
For the particle to remain straight,
. Therefore:
Question (e)
Calculate the mass of a hypothetically singly charged ion that travels in a semicircle of radius
Answer (e)