GATE XE format:nat PYQs & Answers — Page 21

Questions 201–210 of 668. Imported answers require independent review unless marked reviewed.

Topic practice 668 questionsPage 21 of 67

A metal has a certain vacancy fraction at a temperature of 600 K. On increasing the temperature to 900 K, the vacancy fraction increases by a factor of ____________ (round off to one decimal place)

Given: Gas constant, R = 8.31 J mol

and activation energy for vacancy formation, Q = 68 kJ mol

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In a semiconductor, the ratio of electronic mobility to hole mobility is 10. The density of electrons and holes are

and

, respectively. If the conductivity of the material is

, then the mobility of holes is (in

): ____________ (rounded off to nearest integer)

Given: Charge of an electron:

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A pure Silicon wafer is doped with Boron by exposing it to B₂O₃ vapour at an elevated temperature. It takes 1000 seconds to reach a Boron concentration of

at a depth of 1

m. The time taken to reach the same concentration of Boron at a depth of 2

m is (in seconds): ________ (rounded off to nearest integer)

Given: Boron concentration on the wafer surface remains constant.

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The Young’s modulus of a quartz piezoelectric crystal is 100 GPa. The uniaxial stress required to change its polarization by 1% is (give absolute value in GPa) ________ (rounded off to nearest integer)

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A one-dimensional nanowire has a linear electron density of

. The Fermi energy of the system is (in eV) ______ (rounded off to two decimal places)

Given:

where ‘m’ is the mass of an electron

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Two moles of a monoatomic ideal gas at 10 atm and 300 K is expanded isothermally and reversibly to a pressure of 2 atm. The absolute value of work done by the system is (in kJ) __________ (rounded off to two decimal places)

Given: R = 8.31 J mol⁻¹ K⁻¹, 1 atm = 101 kPa

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An electrochemical cell consists of pure Zn electrode (anode) and a hydrogen electrode (cathode) in a dilute Zn²⁺ solution. The overall reaction is:

Zn (s) + 2H⁺ = H₂ + Zn²⁺

If the overall cell potential is +0.690 V, then the value of

is ________ (rounded off to two decimal places)

Given: Pressure of hydrogen gas = 1 atm; Temperature = 298 K;

, where R is gas constant and F is Faraday constant

The standard reduction potential of:

Zn²⁺ + 2e = Zn (E° = −0.762 V) versus Standard Hydrogen Electrode

2H⁺ + 2e = H₂ (E° = 0 V)

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In a Raman spectroscopy experiment done at 300 K, a Raman line is observed at 200 cm⁻¹ (~25 meV). The ratio of the intensity of the Stokes line to that of the Anti-Stokes line is __________ (rounded off to two decimal places)

Given: Boltzmann constant, k = 8.62 × 10⁻⁵ eV K⁻¹

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A rod is subjected to three forces as shown in the figure on the left. An equivalent force system with forces

and moment

is shown in the figure on the right. The value of M (in N-m) is ______ (rounded off to one decimal place).

Diagram for Engineering Sciences question 72

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A simply supported beam of length 3 m is loaded as shown in the figure.

Diagram for Engineering Sciences question 73

The magnitude of the shear force (in kN) at the mid-point of the beam is______(rounded off to one decimal place).

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GATE XE format:nat PYQs

Question 51

Question 52

Question 60

Question 61

Question 62

Question 63

Question 64

Question 65

Question 72

Question 73