3i Infotech Papers: Sample Questions 78 - 79 of 1245

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Question number: 78

» Basic CS » Data Structures

Essay Question▾

Describe in Detail

What is a hash table? When would you can use one?

Explanation

Understanding of Hash table

Understanding of Hash Table

Understanding of Hash table

  • Value is stored in a data structure called hash table.

  • Uses a hash function to compute an index into an array which element will search.

Image of the hash table

Image of the Hash Table

Image of the hash table

  • Also used with key/value pairs to store and retrieve value using key.

  • Hash table access of data becomes very fast if we know the index of the desired data.

  • The average time required to search for an element in a hash table is O (1).

  • Basic operation of hash table:
    • Search: search an element in a hash table.

    • Insert: insert an element in a hash table.

    • Delete: Delete an element from a hash table.

Question number: 79

» Basic CS » Networks

Short Answer Question▾

Write in Short

What is attenuation?

Explanation

  • Degeneration of a signal over distance on a network cable is called attenuation (physical characteristic of the medium like cable).

  • Attenuation refers to reduction in the strength of a signal.

  • Historically measured in dB but it can also be measured as voltage.

  • Applies to both hard-wired and wireless transmissions.

Different types of attenuation include:

  • Deliberate attenuation occurs where a volume control is used to lower the sound level on electronics.

  • Automatic attenuation is a common feature of televisions and other audio equipment to prevent sound distortion by automatic level sensing.

  • Environmental attenuation relates to signal power loss due to the transmission medium.