12th class (Fsc) Physics unit 6 MCQs
26. The substance in which the atoms do not form magnetic dipoles are called:
a. Ferro magnetic
b. Diamagnetic
c. Crystal
d. Para magnetic
27. Insulators have conductivity ranging between:
a. 10-4 to 10+4 (Ωm )-1
b. 10-8 to 10-4 (Ωm )-1
c. 104 to 108 (Ωm )-1
d. 10-10 to 10-20 (Ωm )-1
28. A pentavelent impurity is:
a. Indium
b. Boron
c. Phosphorous
d. Alumimium
29. Young’s modulus for water’s is:
a. 2
b. Zero
c. 3
d. 1
30. In p-type substances, the minority carriers are:
a. Holes
b. Electrons
c. Neutrons
d. Protons
31. The young’s modulus of steel is:
a. 2 x 109 Nm-2
b. 2 x 1011 Nm-2
c. 1.5 x 109 Nm-2
d. 3.9 x 109 Nm-2
32. A solid in which there is no regular arrangement of molecules is called:
a. Glassy solid
b. Crystalline solid
c. Amorphous solid
d. Both A and B
33. Above the curie temperature iron is:
a. Ferromagnetic
b. Paramagnetic
c. Not effected
d. Diamagnetic
34. Which one of the following is polymeric solids?
a. Copper
b. Glass
c. Zinc
d. Nylon
35. Soft magnetic material is:
a. Steel
b. Iron
c. Copper
d. Sodium
36. The critical temperature of Aluminum is:
a. 7.2K
b. 3.72K
c. 8.2K
d. 1.18K
37. The ability of a body to return to its original shape is called:
a. Elasticity
b. Strain
c. Plasticity
d. Stress
38. Which one of the following is ductile substance?
a. Wrought iron
b. Copper
c. Lead
d. All of them
39. A solid having regular arrangement of molecules throughout its structure is called:
a. Glassy solid
b. Amorphous solid
c. Crystalline solid
d. Polymeric solid
40. Which of the following has least hysteresis loop area?
a. Soft iron
b. Steel
c. Labalt
d. Wrought iron
41. Conductors have conductivities of the order of:
a. 105 (Ω m)-1
b. 103 (Ω m)-1
c. 109 (Ω m)-1
d. 107 (Ω m)-1
42. The ratio of adding impurity in a semi-conductor is:
a. 1 to 105
b. 1 to 103
c. 1 to 106
d. 1 to 104
43. A vacant or partially filled band is called:
a. Forbidden band
b. Fermi band
c. Conduction band
d. Valence band
44. Out of the following which material is brittle:
a. High carbon steel
b. Wrought iron
c. Tungest
d. Copper
45. If stress is increased beyond the elastic limit of material, it becomes permanently changed, this behavior of material is called:
a. Yield-Strength
b. Elasticity
c. Ultimate tensile strength
d. Plasticity
46. A material which is insulator at 0 K and conduct at room temperature is:
a. Germanium
b. Silver
c. Polythene
d. Lead
47. Which one pair belongs to acceptor impurity:
a. Antimony, indium
b. Arsenic, Phosphorous
c. Arsenic, Antinomy
d. Boron, Gallium
48. Glass and high carbon steel are examples of:
a. Soft substances
b. Ductile substances
c. Hard substances
d. Brittle substances
49. Good conductors have conductivities of the order:
a. 102 (Ω m)-1
b. 10-7 (Ω m)-1
c. 10-2 (Ω m)-1
d. 107 (Ω m)-1
50. Minority carriers in p-types, substances are:
a. Protons
b. Holes
c. Portions
d. Electrons
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