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1 Which one of the following is the property of incidence matrix?
2
What are the properties of a tree in a network graph?
1. It consists of all the nodes of the graph
2. If the graph has N number of nodes, the tree will have (N–1) branches
3. There will be only one closed path in the tree
3
What are the advantages of capacitive transducers?
1. They are extremely sensitive
2. They have a high input impedance and therefore the loading effects are minimum
3. They have a good frequency response
4
The capacitive transducer works on the principle of change of capacitance which may be caused by change in
1. Dielectric constant
2. Overlapping area of plates
3. Distance between the plates
5
A platinum thermometer has a resistance of 100Ω at 25 °C. The resistance at 65°C for its resistance temperature co-efficient of 0.00392/°C will be nearly
6
Which of the following line telemetry systems are available?
1. Voltage telemetry system
2. Current telemetry systems
3. Positions telemetry systems
4. Resistive telemetry systems
7
. What are the salient features of thermistors?
1. They are compact, rugged and inexpensive
2. They have good stability when properly aged
3. The response time of thermistors can vary from a fraction of a second to minutes, depending on the size of the detecting mass and thermal capacity of the thermistor
8
What are the advantages of resistance potentiometer?
1. They are inexpensive
2. They are useful for measurement of large amplitudes of displacement
3. Their electrical efficiency is very high and they provide sufficient output to permit control operations without further amplification
9
Unit step response of first order system with transfer function
10
A thermometer reads 95.45°C and the static correction given in the correction curve is – 0.08°C. The true value of temperature will be
11
Which of the following methods are used for measurement of low resistance?
1. Ammeter voltmeter method
2. Kelvin’s double bridge method
3. Maxwell’s bridge method
4. Potentiometer method
12
Which of the following methods are used for producing damping torque in analog instruments?
1. Air friction damping
2. Fluid friction damping
3. Eddy current damping
4. Electromagnetic damping
13
A 1-mA meter movement with an internal resistance of 100? is to be converted into a 0-100 mA ammeter. The value of shunt resistance will be
14
Which one of the following is composed of two characteristics: conformity and the number of significant figures to which a measurement may be made?
15
Which of the following statements are correct for superconductors?
1. A substance loses its electrical resistance below certain temperature.
2. Superconducting elements have greater electrical resistivity at room temperature
3. On adding impurities to super conducting elements its transition temperature is increased
16
Type-I classified superconducting materials on the basis of magnetic response are completely in diamagnetic state where magnetic field is excluded from the body of material due to the phenomenon, known as
17
In a 440 V, 50 Hz transformer, the total iron loss is 2300 W. When the applied voltage is 220V at 25 Hz, the total iron loss is 750 W. The eddy current loss at the normal voltage and frequency will be
18
The detailed information regarding the mechanism of fracture is available from microscopic examination, normally using scanning electron microscopy, and its study is termed as
19
The detailed information regarding the mechanism of fracture is available from microscopic examination, normally using scanning electron microscopy, and its study is termed as
20
Which one of the following is commonly used piezolectric ceramics?
21
A transformer core is wound with a coil carrying an alternating current at a frequency of 50 Hz. The magnetization is uniform throughout the core volume of 0.01m3 , the hysteresis loop has an area of 60,000 units when the axes are drawn in units of 10–4 Wbm–2 and 102 Am-1. The power loss due to hysteresis will be
22
Which of the following point are important on the viscosity scale in the fabrication and processing of glasses?
1. Softening point
2. Working point
3. Melting point
23
Ceramic materials are
24
The critical stress σc for crack propagation in a brittle material, using the principles of fracture mechanics is
Where: E = Modulus of elasticity
| γs = Specific surface energy |
α = one half the length of an internal crack
25
A circular dislocation loop has edge character all round the loop and this dislocation can glide only on a surface that contains
26
The theoretical density ρ for the crystal structure of a metallic solid as
Where: n = number of atoms associated with each unit cell VC = Volume of unit cell A = Atomic weight NA = Avogadro’s number
27
Which of the following materials are used for high-technology applications?
1. Semi conductors
2. Bio materials
3. Smart materials
28
Which of the following are the active materials of a lead acid cell?
1. Lead peroxide (PbO2 ) for positive plate
2. Sponge lead (Pb) for negative plate
3. Concentrated sulphuric acid (H2 SO4 ) as electrolyte
4. Dilute Sulphuric acid (H2 SO4 ) as electrolyte
29
The cells are connected in two rows in parallel to pass a current of 6A through an external rersistance 0.7Ω . If the electromotive force of each cell is 2.1 volts and internal resistance 0.5 Ω , the minimum number of cells will be
30
The value of total potential differencebetween the electodes created, when the cell is not connected to an external circuit is known as its
31
Two coils are connected in parallel and a voltage of 200 V is applied to the terminals. The total current taken is 15 A and the power dissipated in one of the coils is 1500 W, the resistance of each coil will be nearly
32
In a 4-pole dynamo the flux/pole is 15 mWb. If armature is driven at 600 rpm the average emf induced in one of the armature conductors will be
33
Two capacitors of 80 µFand 50 µF are connected in series. When 200 V at 50 Hz are applied across the series circuit, the maximum energy stored in the circuit will be
34
Consider the following data regarding the name plate of 1-phase, 4-pole induction motor: Output = 373 W; 230V, frequency = 50Hz, input current = 2.9 A, power factor = 0.71, speed = 1410 rpm. The efficiency of motor will nearly
35
A 200 kVA, 3300/240 V, 50Hz single phaseV transformer has 80 turns on the secondary winding. Assuming an ideal transformer the primary current I1 and secondary current I2 on full load are nearly
36
Crest factor for an alternating current source is the ratio of
37
A car having an axle of 2m length is travelling with 72 km/h at a vertical component of the earth’s magnetic field of 40µ Wb /m² , the emf generated in the axle of a car will be
38
Ohm’s law is applicable to
39
According to Kirchhoff’s voltage law, the algebraic sum of all the voltage in any closed loop of a network is always
40
The quantum efficiency η for the photo detector is
41
The advantage of ILD over LED is
42
Which one of the following statements regarding slew rate is correct?
43
If the bias current in the IC-741 op-amp is IQ = 19 ?A and the internal frequency compensation capacitor C1 = 30pF, the slew rate of the op-amp will be nearly
44
If an op-amp having specified signal bandwidth (BW) of 1 MHz and closed loop gain ACL = 200 V/mV, the cut-off frequency f c will be
45
The overall decibel (dB) voltage gain of a multistage amplifier is
46
The advantage of using a class-B push pull transistor amplifier over a class-A push pull transistor amplifier is
47
Consider an n-channel MOSFET with parameters Kn = 0.25 mA/V2 , VTN = 1V, ? = 0, Cgd = 0.04 pF and Cgs = 0.2 pF If the transistor is biased at VGS = 3V, the unity gain bandwidth of an FET will be
48
Silicon dioxide (SiO2 ) is used in ICs, because it
49 A single phase full wave rectifier uses semiconductor diodes. The transformer voltage is 35 V rms to center tap. The load consists of a 40 F? capacitor in parallel with a 250? resistor. The diode and transformer resistances and leakage reactance are neglected. If the power line frequency is 50 Hz, the dc current in the circuit will be.