Q. 43

Expert-verified
Found in: Page 991

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

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

# An advanced computer sends information to its various parts via infrared light pulses traveling through silicon fibers. To acquire data from memory, the central processing unit sends a light-pulse request to the memory unit. The memory unit processes the request, then sends a data pulse back to the central processing unit. The memory unit takes to process a request. If the information has to be obtained from memory in , what is the maximum distance the memory unit can be from the central processing unit?

The maximum distance between the memory unit and the central processing unit is .

See the step by step solution

## Step 1: Given information

We have been given that an advanced computer sends information to its various parts via infrared light pulses traveling through silicon fibers. The memory unit takes to process a request. The time taken by the memory unit to deliver the information back to the central processing unit is .

We need to find the the maximum distance between the memory unit and the central processing unit.

## Step 2: Simplify

The refractive index of silicon is .

The speed of light through the silicon fibers can be calculated by :

, where is speed of light in silicon fibers, is speed of light in vacuum, is the refractive index of silicon.

Substituting and , we get:

On simplifying, we get:

The time taken by the infrared light to travel to the memory unit from the central processing unit is

We can find the total distance travelled by the infrared light by the following formula:

Substituting the values of and , we get:

The distance between the central processing unit and the memory unit is half of the total distance travelled:

Substituting the value of , we get: