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(a) Determine the electric field that yields the desired result. size: ___N/C di

ID: 1372948 • Letter: #

Question

(a) Determine the electric field that yields the desired result.
size: ___N/C
dir:  ---Select--- +x dir -x dir +y dir -y dir none of these

(b) Suppose the electric field is to be produced by a parallel-plate capacitor with a plate separation of 2.5 cm. What potential difference is required between the plates?
___V

(c) Which plate in the figure should be positively charged?
(Make sure you understand why.)

bottom or top?

A beam of protons with various speeds is directed in the positive x direction. The beam enters a region with a uniform magnetic field of magnitude 0.55T pointing into the page, as shown below. It is desired to use a uniform electric field (in addition to the magnetic field) to select from this beam only those protons with a speed of 1.46 (a) Determine the electric field that yields the desired result. size: ___N/C dir: ---Select--- +x dir -x dir +y dir -y dir none of these (b) Suppose the electric field is to be produced by a parallel-plate capacitor with a plate separation of 2.5 cm. What potential difference is required between the plates? ___V (c) Which plate in the figure should be positively charged? (Make sure you understand why.) bottom or top? 10^5 m/s; that is, only these protons should be undeflected by the two fields.

Explanation / Answer

a)

The electric field between the plates is

E / B = v

E = B v

= (0.55 T ) ( 1.46 *10 ^5 m/s )

= 80300 V/m

b)

Potential difference between the plates is

V = E d = ( 80300 V / m ) ( 2.5*10^ -2 m ) = 2007.5 V

c)

From right hand rule the electric field direction is downward. so the positive charged plate is upper plate.