# Basic CS-Operating System [3i Infotech Placement]: Sample Questions 36 - 37 of 89

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## Question 36

Operating System
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### Describe in Detail

Essay▾

What is the difference between MOV and MVI?

### Explanation

MOV:

• Copies contents of the source register into the destination register.
• Contents of the source register are not altered.
• If one of the operands is a memory location - location is specified by contents of the HL registers.
• Example: MOV B, C or MOV B, M

MVI:

• The data is stored in the destination register or memory.
• If the operand is a memory location- location is specified by the contents of the HL registers.
• Example: MVI B, H or MVI M, H

## Question 37

Operating System

### Question

MCQ▾

Which of the following is not an essential condition for interference?

### Choices

Choice (4)

a.

The two interfering waves must be propagated in almost the same direction or the two interfering waves must intersect at a very small angle

b.

Amplitude of the two waves should be the same

c.

The waves must have the same time period and wavelength

d.

The interfering beams of light must originate from the same source

b.

### Explanation

• The phase difference between the two waves should not change with time.
• If the phase difference between the waves, changes with time, the intensity at a given point will be a function of time and fringe pattern will not be clean.
• The phase difference between the waves can be maintained by using coherent light sources or by using waves derived from one single source.
• The two waves must also have same state of polarization i.e.. their electric field vectors must point in the same direction
• If the electric field vectors of two waves point in orthogonal direction the resultant intensity will not depend upon the phase difference.
• If the electric field vectors of these waves are not completely orthogonal, the components which are parallel to each other will interfere.
• In this case the difference between maximum and minimum intensity will not be as large as in the case when two waves are in the same state of polarization.
• The two interfering waves should have same wavelength.
• If the wavelengths are very different, the interference cannot take place.
• In the case when there is slight variation in wavelength, the resultant wave behaves like a group of waves and result in beat formation.

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