Q. 26

Expert-verified
Found in: Page 654

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# Two diameter disks face each other, apart. They are charged to . a. What is the electric field strength between the disks? b. A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?

a. The electric field strength between the disks is

b. The proton has launch speed of to reach the positive disk

See the step by step solution

## Step 1 : Given information and formula used

Given :

Two disks of diameter each :

Distance between disks :

They are charged to :

Theory used :

gives the electric field inside the capacitor.

Where denotes the disk's surface area. The charge on the disk is The conservation of energy law states that

, where

initial kinetic energy

= initial potential energy

= final kinetic energy

final potential energy

## Step 2 : Calculating the electric field strength between the disks

(a) Using the equation , we have :

## Step 3 : Calculating the launch speed of the proton

(b) The proton's velocity when it hits the capacitor's positive disk is.

So applying conservation of energy to find the initial velocity of proton :

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