Proton in magnetic and electric field

AI Thread Summary
To ensure a proton moves un-deflected in a combined magnetic and electric field, the electric field must be oriented in the -y direction. The magnetic field, directed in the -z direction, exerts a force on the proton moving in the +x direction, which necessitates an opposing electric field to balance the forces. The relationship between the electric and magnetic forces is described by the equation qE = qVB. The discussion highlights the application of the right-hand rule (RHR) to determine the direction of forces acting on the proton. The consensus confirms that the correct orientation for the electric field is indeed -y.
syhpui2
Messages
23
Reaction score
0

Homework Statement




As shown in the figure below, a proton moves in the +x direction with speed v and is immersed in both, a uniform magnetic field, B, oriented in the -z direction, and a uniform electric field, E (not shown in the diagram). What electric field orientation is required in order for the proton to move un-deflected through the combined magnetic and electric field region?
(a) +y direction
(b) -y direction
(c) +z direction

Answer is B.

http://i.imgur.com/1G80T.png

1G80T.png


Homework Equations



qE=qVB

The Attempt at a Solution



I used RHR, I get answer A...
 
Physics news on Phys.org
Which way does the B field push on the proton?
Which way should the E field push on it?
 
Delphi51 said:
Which way does the B field push on the proton?
Which way should the E field push on it?

Which way does the B field push on the proton? Along x-axis
Which way should the E field push on it? Opposite direction of qvb?
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Back
Top