SELECT * FROM question_mgmt as q WHERE id=1755 AND status=1 SELECT id,question_no,question,chapter FROM question_mgmt as q WHERE courseId=3 AND subId=9 AND chapterId=56 and ex_no='2' AND status=1 ORDER BY CAST(question_no AS UNSIGNED) CBSE Free NCERT Solution of 12th chemistry The Solid State explain the following terms with suitable examples

Question:

Explain the following terms with suitable examples:

(i) Schottky defect

(ii) Frenkel defect

(iii) Interstitials and

(iv) F-centres

Answer:

(i) Schottky defect – It was discovered by German scientist Schottky in 1930. It is basically a vacancy defect in ionic solids. In order to maintain electrical neutrality, the number of missing cations and anions are equal.

(ii) Frenkel defect – It was discovered by a Russian scientist Frenkel in 1926. It arises when an ion is missing from its normal position and occupies an interstitial site between the lattice points. In this case the crystal remains electrically neutral because the number of cations and anions remains the same.

(iii) Interstitials defect – When some constituent particles occupy an interstitial positions, the crystal is said to have a interstitial defect. Thus defect increases the density of the substance.

(iv) F-centres – During an anion vacancy, the electrons trapped in anion vacancies are called as F centres. It is originated from a German word farbenzenter which means colour centre.


SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='3' AND subId='9' AND ex_no!=0 AND status=1 and id!=1755 ORDER BY views desc, last_viewed_on desc limit 0,10
SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='3' AND subId='9' AND ex_no!=0 AND status=1 and id!=1755 ORDER BY last_viewed_on desc limit 0,10

Comments

  • Answered by Ekta Mehta
  • 4 months ago

Taking Screenshots on your Samsung Galaxy M31s is very easy and quick.


  • Answered by Ekta Mehta
  • 4 months ago

Taking Screenshots on your Samsung Galaxy M31s is very easy and quick.


  • Answered by Ekta Mehta
  • 4 months ago

Taking Screenshots on your Samsung Galaxy M31s is very easy and quick.


Comment(s) on this Question