Question regarding point charge and charged metal plate? - Multi choice (1 Viewer)

[Lucas_]

Hi

I have 2 questions from my weekend homework that I am struggling with.



I think the answer is either C or A. If I had to pick I would say C since the charge is attracted to the plate and field lines go from positive to negative.


I think the answer is either C or D. If I had to pick I would say D because particles in a uniform field travel in a circle, and a stronger field would force (maybe?) the particle into a greater arc? Really not sure!

Please help guys, thanks

 

[Timske]

Not a phys wizz but 8 should be C not sure about 6

 

[nightweaver066]

With 6, and







From observing this equation, increasing the magnetic field strength will decrease the radius where as increasing velocity of the charged particle will increase the radius.

Therefore it is C.

 

[Rathaen]

Just to clarify on question 8, the answer is C because field lines for electric charges always point in the direction that a positive charge would move if placed in the field. Thus away from the positive charge, and towards the negatively charged plate.

 

[John Rips]

I tutor Physics and can assure you both are C. Your reasoning in Q8 is correct, field lines run from + to neg.
For Q 6. Again its C and Nightweaver has hit it on the button. Look at Fmagnetic = qvB which contributes to Fcentripetal = mv^2/r. Looking at your choices, increase in q or B, (answers A and D) means a greater force acting on the particle so it will spiral in a smaller radius. Less mass also results in a smaller radius. The drawing is the basic of a mass spectrometer where elements are vaporised and ionised, then accelerated through a device called a velocity selector to ensure all particles entering the magnetic field have the same velocity. Thus the radius of curvature is directly proportional to the mass of the ion. This machine is accurate enough to separate heavy metal isotope.