Why is a laser required to read data from an optical disk?
What will be an ideal response?
The laser produces coherent light; that is, light at a constant frequency and phase (unlike normal white light which contains a wide range of frequencies and phases). A property of coherent light is that when it falls partially on a step whose height is one quarter of a wavelength from the base, some of the light (that hits the
floor) travels further by one half a wavelength than the light reflected off the top. These two beams interfere destructively and cancel. Thus, the laser can detect bumps (pits and land) on the surface of the disk. The laser beam can also be tightly focused.
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To access the eraser tools after using a different tool, press the ____ key.
a. F b. E c. right bracket ( ] ) d. F3
What type of routing protocol uses information about the distances between networks rather than the amount of time it takes for traffic to make its way from the source network to the destination network?
A. triggered B. link-state C. distance vector D. split horizon
Which of the following is an alternative to a combo box?
A) Make it a required field B) Add a data validation rule C) Set a tab order D) Key in the field
After creating a report, you view it in Layout view, you see that the report is extremely wide. You decide to narrow the state field, since the states are displayed using two-letter abbreviations. Explain how you would narrow the width of the state field
What will be an ideal response?