TN 12TH PHYSICS - Online Test

Q1. Doping a semiconductor results in
Answer : Option C
Explaination / Solution:
No Explaination.


Q2.

A thin semi-circular conducting ring (PQR) of radius r is falling with its plane vertical in a horizontal magnetic field B, as shown in the figure.


The potential difference developed across the ring when its speed v , is
Answer : Option D
Explaination / Solution:


Q3. Which one of the following is the natural nanomaterial.
Answer : Option A
Explaination / Solution:
No Explaination.


Q4. If the amplitude of the magnetic field is 3 × 10−6 T, then amplitude of the electric field for a electromagnetic waves is
Answer : Option D
Explaination / Solution:


Q5. Roasting of sulphide ore gives the gas (A).(A) is a colourless gas. Aqueous solution of (A) is acidic. The gas (A) is
Answer : Option C
Explaination / Solution:
No Explaination.


Q6. Boric acid is an acid because its molecule
Answer : Option D
Explaination / Solution:

B(OH)3 + H2O ↔ [B (OH)4 + H+



Q7. An element belongs to group 15 and 3 rd period of the periodic table, its electronic configuration would be
Answer : Option D
Explaination / Solution:
No Explaination.


Q8. Among the transition metals of 3d series, the one that has highest negative ( M2+ /M) standard electrode potential is
Answer : Option A
Explaination / Solution:
No Explaination.


Q9. A complex has a molecular formula MSO4 Cl. 6H2O .The aqueous solution of it gives white precipitate with Barium chloride solution and no precipitate is obtained when it is treated with silver nitrate solution. If the secondary valence of the metal is six, which one of the following correctly represents the complex?
Answer : Option C
Explaination / Solution:

Molecular formula: MSO4Cl. 6H2O .

Formation of white precipitate with Barium chloride indicates that SO42- ions are outside  the coordination sphere, and no precipitate with AgNO3 solution indicates that the Cl ions are inside the coordination sphere.Since the coordination number of M is 6, Cl and 5 H2O are ligands, remaining 1 H2O molecular and SO42-  are in the outer coordination sphere.


Q10. The ratio of close packed atoms to tetrahedral hole in cubic packing is
Answer : Option B
Explaination / Solution:

if number of close packed atoms =N; then,

The number of Tetrahedral holes formed = 2N

number of Octahedral holes formed = N

therefore N:2N = 1:2