Match
List-I with
List-II and select the correct answer using the options given below:
List-I (Material/Characteristics)List-II (Superconductor kind)
a. Incomplete Meissner's effect, high critical field and transition temperature. Absence of Silsbee's rule
1. Hard superconductor
b. Meissner's effect and Silsbee's rule
2. Soft superconductor
c. Amorphous thin films of Be, Bi and Fi
3. Superconductor
A. a-1, b-3, c-2
B. a-1, b-2, c-3
C. a-3, b-2, c-1
D. a-3, b-1, c-2
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Total number of crystal system is
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When copper is added to silver in small quantity so as to form an alloy, the resistivity of such an alloy is
A. equal to the resistivity of copper
B. equal to the resistivity of silver
C. greater than the resistivity of copper
D. in between the resistivity of silver and copper
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The relative permeability is less than 1 in
A. ferromagnetic materials
B. diamagnetic materials
C. paramagnetic materials
D. ferrites
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The outermost electronic configuration a cobalt atom is 3d7 4s2 . Its magnetic moment is-
A. 9 Bohr magnetrons
B. 7 Bohr magnetrons
C. 5 Bohr magnetrons
D. 3 Bohr magnetrons
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The critical stress σc for crack propagation in a brittle material, using the principles of fracture mechanics is
A. ( 2 π α 2 E γ s ) 2 1
B. ( 2 π α 3 E γ s ) 2 1
C. ( π α 2 E γ s ) 2 1
D. ( π α 3 E γ s ) 2 1
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The wavelength of light emitted by a GaAs laser is 8670 × 10-10 m. Given Planck's constant = 6.6256 × 10-34 Js, velocity of light = 2.998 × 108 ms-1 and 1eV = 1.602 × 10-19 J, the energy gap in GaAs is
A. 0.18 eV
B. 0.7 eV
C. 1.43 eV
D. 2.39 eV
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Blood flow can be measured using the electromagnetic principle because blood has a high
A. magnetic induction
B. electrical resistivity
C. electrical conductivity
D. impedance
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n - type silicon is obtained by doping silicon with
A. Germanium
B. Aluminum
C. Boron
D. Phosphorus
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The value of critical current density in a superconductor depends upon
A. 1, 2 and 3
B. 1 and 3 only
C. 2 and 3 only
D. 1 and 2 only
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Consider the following statements pertaining to the resistance of a conductor:
A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3 only
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Which one of the following is commonly used piezoelectric ceramics?
A. Yttrium oxide (Y2 O2 )
B. Boron carbide (B4 C)
C. Barium titanate (BaTiO3 )
D. Tungsten carbide (WC)
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The ratio of ionic radii of cations i.e. rC and that of Anions i.e. rA for stable and unstable ceramic crystal structure, is:
A. Less than unity
B. Greater than unity
C. Unity
D. Either lesser or greater than unity
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Which of the following are the advantages of Silicon over Insulator (SOI)?
A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only
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Which of the following materials are used for high-technology applications?
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3
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In a superconducting magnet, wires of superconducting material are embedded in the thick copper matrix, because while the material is in the superconducting state:
A. The leakage current passes through copper part
B. Copper part helps in conducting heat away from the superconductor
C. Copper part helps in overcoming the mechanical stress
D. Copper acts as an insulating cover for superconductor
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The energy gap of a superconductor
A. Is independent of temperature
B. Increase with temperature
C. Is maximum at a critical temperature
D. Is minimum at a critical temperature
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The most suitable material for making an LDR (Light dependent resistor) is a semiconductor material having
A. E g >> h υ
B. E g > h υ
C. E g = h υ
D. E g << h υ
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In an intrinsic semiconductor, the mobility of electron in the conduction band is
A. zero
B. less than the mobility of holes in the valence band
C. equal to mobility of holes in the valence band
D. greater than the mobility of holes in the valence band
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The ceramic materials are
A. Inorganic substances
B. Brittle
C. Good Thermal insulators
D. All of the above
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