Free Printable NT SURPRISE TEST

1.

A network contains only an independent current source and resistors . If the values of all resistors are doubled, the value of the node voltages will

a)

(a) becomes half

b)

(b) remain unchanged

c)

(c) become double

d)

(d) none of these

2.

Superposition theorem is not applicable to networks containing

a)

(a) nonlinear elements

b)

(b) dependent voltage source

c)

(c) dependent current source

d)

(d) transformers

3.

The condition for maximum power transfer in a dc network is

a)

(a) R_th =R_L

b)

(b) R =R_th+ R_L

c)

(c) R = R_th/R_L

d)

(d) R = R_th-R_L

4.

If each branch of a delta network has resistance √3R, then each branch of the equivalent wye network has resistance

a)

(a)
$\frac{R}{\sqrt{3}}$

b)

(b) 3R

c)

(c) $3\sqrt{3}R$

d)

$\frac{R}{3}$

5.

A current is said to be alternating when it changes in

a)

(a) Magnitude only

b)

(b) direction only

c)

(c) both magnitude and direction

d)

(d) neither magnitude nor direction

6.

A alternating current of 50 Hz frequency and 100 A maximum value is given as

a)

$i=200\sin628t$

b)

$i=100\sin314t$

c)

$100\sqrt{2}\sin314t$

d)

$100\sqrt{2\ \ }\sin157t$

7.

A constant current of 2.8 A exists in a resistor. The rms value of the current is

a)

(a) 2.8 A

b)

(b) 2 A

c)

(c) 1.4 A

d)

(d) undefined

8.

In a two element series circuit, the applied voltage and resultant current are respectively v(t) = 50+50 sin (5x10³t) and i(t) = 11.2sin(5x10³t+63.4⁰) . The nature of the elements would be

a)

(a) RL

b)

(b) RC

c)

(c) LC

d)

(d) Neither R , nor L, nor C

9.

In a series RLC circuit, R = 2k Ώ, L = 1 H, C = $\frac{1}{400}\mu F$ The resonant frequency is

a)

$2\times10^4Hz$

b)

$\frac{1}{\pi}\times10^4Hz$

c)

$10^4Hz$

d)

$2\pi\times10^4Hz$

10.

In a series RLC circuit at resonance, the magnitude of the voltage developed across the capacitor

a)

(a) is always zero

b)

(b) can never be greater than the input voltage

c)

(c) can be greater than the input voltage, however it is 90 ⁰ out of phase with the input voltage

d)

(d) can be greater than the input voltage and is in phase with the input voltage

11.

The overall inductance of two coils connected in series, with mutual inductance aiding self inductance is L₁ ; with mutual inductance opposing self inductance, the overall inductance is L₂. The mutual inductance M is given by

a)

$L_1+L_2$

b)

$L_1-L_2$

c)

$\frac{1}{4}\left(L_1-L_2\right)$

d)

$\frac{1}{2}\left(L_1+L_2\right)$

12.

Two coupled coils connected in series have an equivalent inductance of 16 mH or 8 mH depending on interconnection. Then the mutual inductance M between the coil is

a)

$12\ mH$

b)

$8\sqrt{2}mH$

c)

$4\ mH$

d)

$2\ mH$

13.

The Laplace transform of $e^{at}\cos\alpha t$ is equal to

a)

$\frac{\left(s-a\right)}{\left(s-a\right)^2+\alpha^2}$

b)

$\frac{\left(s+a\right)}{\left(s+a_{ }\right)^2+\alpha^2}$

c)

$\frac{1}{\left(s-a\right)^2}$

d)

None of the Above

14.

Two port networks are connected in cascade. The combination is to be represented as a single two port network. the parameters are obtained by multiplying the individual

a)

(a) z-parameter matrix

b)

(b) h- parameter matrix

c)

(c) y- parameter matrix

d)

(d) ABCD parameter matrix

15.

if a two port network is passive, then we have , with usual notation , the following relationship for symmetrical network

a)

(a) h₁₂= h₂₁

b)

(b) h₁₂= -h₂₁

c)

(c) h₁₁h₂₂ - h₁₂h₂₁=1

d)

(d) h₁₁= h₂₂

16.

Total instantaneous power supplied by a three phase ac supply to a balanced R-C load is

a)

(a) zero

b)

(b) constant

c)

(c) pulsating with zero average

d)

(d) pulsating with non zero average

17.

Three equal impedances are first connected in delta across a three phase balanced supply. if the same impedances are connected in star across the same supply

a)

(a) Phase current will be one third

b)

(b) line current will be one third

c)

(c) power consumed will be one third,

d)

(d) none of the above.

18.

A three phase load is balanced if all three phases have the same

a)

(a) impedance

b)

(b) power factor

c)

(c) impedance and power factor

d)

(d) none of the above

19.

Short circuit Admittance parameter is the other name of

a)

(a) Z- parameter

b)

(b) Y- Parameter

c)

(c) h-Parameter

d)

(d) ABCD Parameter

20.

Three identical resistors connected in star carry a line current of 12 A. if the same resistors are connected in delta across the same supply , the line current will be

a)

(a) 12 A

b)

(b) 4 A

c)

(c) 8 A

d)

(d) 36 A

NT SURPRISE TEST

Total questions: 20

Worksheet time: 10mins

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