Legal Metrology • Electrical Engineering Paper-I
In a delta connected polyphase circuit, the line current iL is related to phase current iPh
A)
iL = √3 iPh
B)
iL = 3 iPh
C)
iL = iPh / √3
D)
iL = iPh
In the context of Unmapped / long tail, the most appropriate and technically accurate answer is 'iL = iPh' (Option D).
Legal Metrology • Electrical Engineering Paper-I
A small swamping resistance is put in series with operating coil of a moving coil ammeter in order to compensate for the effects of ............
A)
Temperature variation
B)
External magnetic fields
C)
Hysteresis loss
D)
None of the above
A small series “swamping” resistance reduces the temperature coefficient of the moving-coil instrument.
Legal Metrology • Electrical Engineering Paper-I
A 50V range voltmeter has a sensitivity of 20 kΩ/V. The total resistance of the voltmeter is
A)
2.5kΩ
B)
0.4kΩ
C)
10kΩ
D)
1MΩ
Voltmeter resistance = sensitivity×range = 20 kΩ/V×50 V=1 MΩ.
Legal Metrology • Electrical Engineering Paper-I
Two coils having equal resistance but different inductances are connected in series. The time constant of the series combination is the
A)
Sum of the time constants of the individual coils
B)
Average of the time constants of individual coils
C)
Geometric mean of the time constants of the individual coils
D)
Product of the time constants of the individual coils
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'Product of the time constants of the individual coils' (Option D).
Legal Metrology • Electrical Engineering Paper-I
A uniform electric field and a uniform magnetic field are produced, pointed in the same direction. An electron is projected with its velocity pointed in the same direction
A)
the electron will turn to its right
B)
the electron will turn to its left
C)
the electron velocity will increase
D)
the electron velocity will decrease
With E and v parallel, the magnetic force is zero while the electron’s electric force opposes its velocity, reducing the speed.
Legal Metrology • Electrical Engineering Paper-I
Characteristic wave impedance is
A)
E/H
B)
V/I
C)
E1/E2
D)
H1/H2
Based on established principles in Electrical / Electronics Engineering, the correct and most clinically/technically appropriate choice is 'E/H' (Option A).
Legal Metrology • Electrical Engineering Paper-I
If the resistance in a series RC circuit is increased, the magnitude of the phase
A)
Increases
B)
Remains the same
C)
Decreases
D)
Changes in an indeterminate manner
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'Remains the same' (Option B).
Legal Metrology • Electrical Engineering Paper-I
At half-power frequencies, the current in a series RLC circuit is
A)
1/√2 x current at resonance
B)
1/2 x current at resonance
C)
1/√3 x current at resonance
D)
1/2 x current at resonance
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is '1/2 x current at resonance' (Option B).
Legal Metrology • Electrical Engineering Paper-I
A 3H inductor has 2000 turns. How many turns must be added to increase the inductance to 5H?
A)
1000 turns
B)
2500 turns
C)
2582 turns
D)
582 turns
In the context of Unmapped / long tail, the most appropriate and technically accurate answer is '1000 turns' (Option A).
Legal Metrology • Electrical Engineering Paper-I
Fringing effect is ignored in a magnetic circuit if air-gap is
A)
Large
B)
Small
C)
Very large
D)
None of the above
Fringing can be neglected when the air gap is small relative to pole dimensions.
Legal Metrology • Electrical Engineering Paper-I
At t=0 with zero initial condition, which of the following acts as open circuit?
A)
Inductor
B)
Capacitor
C)
Resistor
D)
All of the above
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'All of the above' (Option D).
Legal Metrology • Electrical Engineering Paper-I
A DC voltage V is applied at time t=0 to a series circuit consisting of resistor R and capacitor C. The current in the circuit at time t is
A)
(V/R) e^(-t/RC)
B)
(V/R) e^(t/RC)
C)
V e^(-t/RC)
D)
V e^(t/RC)
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'V e^(t/RC)' (Option D).
Legal Metrology • Electrical Engineering Paper-I
A large value of the exchange interaction energy in a ferromagnetic material implies
A)
Large saturation magnetization
B)
High Curie temperature
C)
High melting point
D)
Large diamagnetic susceptibility
A large exchange interaction favors parallel spin alignment and corresponds to a higher Curie temperature.
Legal Metrology • Electrical Engineering Paper-I
Poles and zeros of a driving point function of a network are simple and interlace on the iw axis. The network consists of elements
A)
R and C
B)
L and C
C)
R and L
D)
R, L and C
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'R and L' (Option C).
Legal Metrology • Electrical Engineering Paper-I
When the magnetic vector of an EM wave is parallel to the boundary surface and electric vector is parallel to the plane of incidence, the polarization is
A)
Vertical
B)
Horizontal
C)
Elliptical
D)
Either (b) or (c)
Based on established principles in Electrical / Electronics Engineering, the correct and most clinically/technically appropriate choice is 'Horizontal' (Option B).
Legal Metrology • Electrical Engineering Paper-I
Five cells each of emf E and internal resistance r are connected in series. If due to oversight, one cell is connected wrongly, then equivalent emf and internal resistance of the combination are
A)
3E and 5r
B)
5E and 5r
C)
3E and 3r
D)
5E and 4r
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is '3E and 3r' (Option C).
Legal Metrology • Electrical Engineering Paper-I
Three equal resistors are connected as shown in Fig. 1. Find the equivalent resistance between points A and B
A)
3R
B)
R/3
C)
3R/2
D)
2R/3
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'R/3' (Option B).
Legal Metrology • Electrical Engineering Paper-I
Two electrical appliances are connected in parallel to a constant voltage supply. If current in one appliance is less than the second appliance by 1%, then power of the first appliance will be less by
A)
1%
B)
2%
C)
4%
D)
5%
In the context of Unmapped / long tail, the most appropriate and technically accurate answer is '1%' (Option A).
Legal Metrology • Electrical Engineering Paper-I
In the circuit of Figure, the switch S is closed at t=0 with iL(0)=0 and Vc(0)=0. In the steady state, Vc equals
A)
200V
B)
100V
C)
0V
D)
-100V
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is '200V' (Option A).
Legal Metrology • Electrical Engineering Paper-I
Superposition theorem is not applicable to networks containing
A)
Non linear elements
B)
Dependent voltage source
C)
Dependent current source
D)
Transformer
In the context of Electrical / Electronics Engineering, the most appropriate and technically accurate answer is 'Dependent current source' (Option C).
Legal Metrology • Electrical Engineering Paper-I
A resistor and an inductor are connected in series to 220V AC supply. When measured with AC voltmeter, the potential difference across the resistor is 132V. The potential difference across the inductor is,
A)
88V
B)
176V
C)
352V
D)
Cannot be predicted
In series RL, V²=V_R²+V_L², so V_L=sqrt(220²−132²)=176 V.
Legal Metrology • Electrical Engineering Paper-I
Three delta connected resistors absorb 60 kW when connected to a 3-phase line. If the resistors are connected in star, the power absorbed is ................
A)
60kW
B)
20kW
C)
40kW
D)
180kW
For the same line voltage, a delta-to-star conversion reduces phase voltage by √3, so total resistive power becomes one-third: 60/3=20 kW.
Legal Metrology • Electrical Engineering Paper-I
Permanent dipole moment consists of the following angular momentum
A)
Orbital angular momentum of electron
B)
Electron spin angular momentum
C)
Nuclear spin angular momentum
D)
All of them
Permanent molecular magnetic moment can include orbital, electron-spin, and nuclear-spin angular-momentum contributions; D is the inclusive choice.
Legal Metrology • Electrical Engineering Paper-I
The instrument in which springs provide the controlling torque as well as serve to lead current into and out of the operating coil is instruments.
A)
Moving iron
B)
Hot wire
C)
Permanent magnet moving coil
D)
None of the above
In PMMC instruments, spiral springs provide controlling torque and also carry current to/from the moving coil.
Legal Metrology • Electrical Engineering Paper-I
Two long straight parallel conductors, 10cm apart, carry currents 5 A each in opposite directions. Then the magnetic flux density at a point mid-way between them is
A)
Zero
B)
10⁻⁴ T
C)
4x10⁻⁴ T
D)
None of the above
At the midpoint of two opposite 5-A wires 10 cm apart, the fields add; the exact result is 4×10⁻⁵ T, which is absent from the options, so D is the “none of these” choice.
