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Delhi University Entrance Test (DUET) 2020 Previous Year Question Paper With Answer Key

This post was last modified on 27 December 2020

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This download link is referred from the post: DUET Last 10 Years 2011-2021 Question Papers With Answer Key || Delhi University Entrance Test conducted by the NTA

Topic:- ELEC MSC S2

The equation of the plane through the points (1, -1,2), (1, 1, -2) and (-1, 1,2) is

[Question ID = 1584]
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1. x + 3y + 2z - 2 = 0
2. x - y + 2z - 2 = 0
3. 2x + 2y + z - 2 = 0
4. x + y - z - 2 = 0
Correct Answer :-
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• 2x + 2y + z - 2 = 0
Unit vector perpendicular to A = 3î + î + 2k and B = 2î – 2ĵ + 4k vectors is

[Question ID = 1585]
1. ±(3î -ĵ - k)/√14
2. ±(î+j+k)/√3
3. ±(î-j+k)/√3
4. ±(î-j-k)/√3
Correct Answer :-

• ±(î-j-k)/√3
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The two complex numbers Z1 = 2 + i2/√3 and Z2 = √3 + i. The argument of Z1/Z2 in degree is

[Question ID = 1586]
1. 0°
2. 90°
3. 30°
4. 60°
Correct Answer :-

• 0°

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The value of the definite integral ∫ sin x dx from 0 to π/2 is

[Question ID = 1587]
1. 1
2. 0
3. π
4. -π
Correct Answer :-

• 0
If we differentiate the f(x) = x^x then df/dx
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[Question ID = 1588]
1. 1 + logx
2. -x^x(1 + logx)
3. x^x(1 + logx)
4. x^x(logx)
Correct Answer :-

• x^x(1 + logx)
The absolute maximum and minimum values points of x³ - 6x² + 9x - 7 in [0 5] are

[Question ID = 1589]
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1. the point of maxima is 3 and the point of minima is 5
2. the point of maxima is 5 and the point of minima is 0
3. the point of maxima is 5 and the point of minima is 3
4. There is no maxima and minima points in [0 5]
Correct Answer :-
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• the point of maxima is 5 and the point of minima is 3
The Laplace transform of given unit step function f(t-β) = {0 t < β, 1 t > β} is

[Question ID = 1590]
1. e^-2s/β
2. e^-βs/s
3. -e^-2s/s
4. e^-2s
Correct Answer :-

• e^-βs/s
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If 2 and 4 are the eigen values of square matrix A then the Eigen values of A^T are

[Question ID = 1591]
1. 0.5, 0.25
2. 2, 4
3. 4, 16
4. 3, 2
Correct Answer :-

• 2, 4

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The system of equation x - 2y + z = 0, 2x - y + 3z = 0 and λ x + y - z = 0 has non zero solution, if λ is

[Question ID = 1592]
1. λ = 0.4
2. λ = -2
3. λ = 2
4. λ = -0.8
Correct Answer :-

• λ = -0.8
If A is skew-Hermitian, then (iA) is
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[Question ID = 1593]
1. Skew-symmetric
2. Symmetric
3. Hermitian
4. Skew-Hermitian
Correct Answer :-

• Hermitian
The integrating factor of the differential equation dy/dx + y/x = x³ - 3 is

[Question ID = 1594]
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1. 1/x
2. x log x
3. x
4. log x
Correct Answer :-
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• x
The solution of dy/dx - y tan x = y² sec x is given by:-

[Question ID = 1595]
1. y^-1 = sinx + C₁ cos x
2. y^-1 = cosx + c₃ sinx
3. y^-1 = - cosx + c₁ sin x
4. y^-1 = -sinx + c₂ cos x
Correct Answer :-

• y^-1 = -sinx + c₂ cos x
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The family of conic represented by the solution of the differential equation (4x + 3y +1) dx + (3x+2y+1) dy = 0 is

[Question ID = 1596]
1. Parabolas
2. Circle
3. Ellipses
4. Hyperbola
Correct Answer :-

• Hyperbola

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The function f(x)= x³- 6x² + 9x + 25

[Question ID = 1597]
1. maxima at x = 1 and a minima at x = 3
2. a maxima at x = 3 and a minima at x = 1
3. no maxima, but a minima at x = 1
4. a maxima at x = 1,but no minima
Correct Answer :-

• maxima at x = 1 and a minima at x = 3
Consider an optical fiber of 75 µm diameter, core index n₁ = 1.5, and cladding index n₂ = 1.49 for operation at λ = 1.31 µm. How many modes does this fiber support?
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[Question ID = 1598]
1. 244
2. 312
3. 484
4. 188
Correct Answer :-

• 484
When a LED has 2 V applied to its terminals, it draws 100 mA and produces 4 mW of optical power. The LED conversion efficiency from electrical to optical power is:-

[Question ID = 1599]
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1. 3%
2. 4%
3. 5%
4. 2%
Correct Answer :-
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• 2%
Number of electron-hole pairs generated divided by the number of photons is:-

[Question ID = 1600]
1. Dark current
2. Quantum response
3. Photo sensitivity
4. Quantum efficiency
Correct Answer :-

• Quantum efficiency
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If the refractive index of a media is 1.5, the velocity of light in the medium is:-

[Question ID = 1601]
1. 3×10⁸ m/s
2. 1.5×10⁸ m/s
3. 1×10⁸ m/s
4. 2×10⁸ m/s
Correct Answer :-

• 2×10⁸ m/s

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In C language, what is the output of the following code
```
int main()
{ int c; printf("%i",c);
}
```
[Question ID = 1602]
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1. 1
2. 0
3. error
4. 4
Correct Answer :-
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• 0
In C language, what is the output of the following code
```
int main()
{ int i = 4; printf("%d%d",i,i++);
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}
```
[Question ID = 1603]
1. 54
2. 45
3. 44
4. 55
Correct Answer :-

• 54
In C language, what is the output of the following code
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```
int main()
{ int a = 63, b = 9; printf("%d",a>>a/b-2);
}
```
[Question ID = 1604]
1. 1
2. 2
3. 3
4. None of these
Correct Answer :-

• 1
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```
main()
{ int x; x = 4; while (x > 1) { printf("%d",x); x=x-1; }
}
```
[Question ID = 1605]
--- Content provided by FirstRanker.com ---
1. 4323
2. 432
3. 4321
4. 3215
Correct Answer :-
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• 432
In C "switch" statement, each case instance value must be:-

[Question ID = 1606]
1. constant
2. Variable
3. Special symbol
4. None of these
Correct Answer :-

• constant
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If mobility of an electrons in Si at 300 K is 0.16 m²/V.s then the diffusion coefficient of electrons is:-

[Question ID = 1607]
1. 20.7 x 10^-4 m²/s
2. 62.1 x 10^-4 m²/s
3. 6.4 x 10^-2 m²/s
4. 41.4 x 10^-4 m²/s
Correct Answer :-

• 41.4 x 10^-4 m²/s

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If an electric field of 45 V/m is applied to a semiconductor sample whose Hall coefficient is 0.04 m³/C then the current density in the sample is (Given: µ_n = 0.36 m²/V)

[Question ID = 1608]
1. 203 A/cm²
2. 814 A/m²
3. 414 A/m²
4. 650 A/cm²
Correct Answer :-

• 414 A/m²
Radiation recombination lifetime is 0.3 ns from a contact. If the minority carrier mobility is 8000 cm²/V.s at 300 K then the diffusion length for the electron is:-
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[Question ID = 1609]
1. 2.50 µm
2. 1.25 µm
3. 5.00 µm
4. 7.98 µm
Correct Answer :-

• 2.50 µm
Consider a 10 µm diameter p-n junction fabricated in Si. If donor density is 10¹⁵ /cm³ and acceptor density is 10¹⁶ /cm³ then built in potential in the p-n junction is (Given: intrinsic carrier concentration for Si = 1.75 × 10¹⁰ /cm³)

[Question ID = 1610]
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1. 0.31 V
2. 1.12 V
3. 1.42 V
4. 0.63 V
Correct Answer :-
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• 0.63 V
In an n-type GaAs crystal at 300 K, the electron concentration varies as n(x) = 1.5 × 10¹⁵ exp(-x/L) /cm². If the electron diffusion co-efficient is 250 cm²/s then the diffusion current density at x = 0 is (where L = 1.5μm and x > 0)

[Question ID = 1611]
1. 1.5 kA/cm²
2. 1.0 kA/cm²
3. 10.0 kA/cm²
4. 0.4 kA/cm²
Correct Answer :-

• 0.4 kA/cm²
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In a MOSFET the transfer characteristics are used to determine which of the following device parameter?

[Question ID = 1612]
1. threshold voltage and output resistance
2. threshold voltage and transconductance
3. transconductance and output resistance
4. transconductance and channel length modulation
Correct Answer :-

• threshold voltage and transconductance

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The maximum voltage gain obtained from FET having g_m = 5ms and r_d = 20kΩ is

[Question ID = 1613]
1. 100
2. 10
3. 0
4. infinity
Correct Answer :-

• 100
The drain of n-channel MOSFET is shorted to the gate and threshold voltage is 1.5V. If the drain current (I_D) is 2 mA for V_GS = 2.5 V then for V_GS = 3.5 V the I_D is
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[Question ID = 1614]
1. 2 mA
2. 4 mA
3. 8 mA
4. 1 mA
If a BJT has base current 250 µA and emitter current collector current

[Question ID = 1615]
1. 14.75 μΑ and 99
2. 14.75 A and 59
3. 14.75 μΑ and 99.8
4. 14.75 mA and 59
Correct Answer :-

• 14.75 mA and 59

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For the following Lissajous figure, the ratio of frequencies of signals applied to two inputs of CRO is

This download link is referred from the post: DUET Last 10 Years 2011-2021 Question Papers With Answer Key || Delhi University Entrance Test conducted by the NTA

--- Content provided by FirstRanker.com ---

This post was last modified on 27 December 2020

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