In a three-phase power measurement using two-wattmeter method, the power factor can be determined from which relationship?
Answer: A
For two-wattmeter method in three-phase systems: tan(φ) = √3(W₁ - W₂)/(W₁ + W₂), used to calculate power factor.
Q.527Medium
A standard cell has an EMF of 1.0186 V at 20°C with temperature coefficient of -0.0004 V/°C. What will be its EMF at 25°C?
Answer: B
EMF at 25°C = 1.0186 - 0.0004 × (25-20) = 1.0186 - 0.002 = 1.0166 ≈ 1.0170 V.
Q.528Easy
Which bridge circuit is specifically designed to measure inductance with small resistance?
Answer: A
Maxwell bridge is used for measuring inductance (especially with small resistance) in industrial and laboratory applications.
Q.529Medium
In a LVDT (Linear Variable Differential Transformer), when the core is at null position, what happens to the output voltage?
Answer: B
At null position in LVDT, the core is centered, and secondary voltages from both coils cancel out, resulting in zero or minimum output.
Q.530Easy
A pressure transducer has sensitivity of 0.5 V/bar. If input pressure varies from 0-10 bar, what is the output voltage range?
Answer: B
Output voltage = Sensitivity × Pressure = 0.5 × 10 = 5 V for maximum pressure of 10 bar.
Q.531Medium
In a potentiometer method for EMF comparison, if standard cell EMF is 1.018 V with 106.4 cm length, and unknown cell requires 107.8 cm, what is unknown EMF?
A light intensity meter using a photocell shows reading of 500 lux. If the luminous intensity of the source is constant, what happens to the reading when distance is doubled?
Answer: B
Illuminance follows inverse square law: E ∝ 1/d²; when distance doubles, illuminance becomes 41th: 4500 = 125 lux.
Q.535Easy
Which of the following logic gates produces output 1 only when all inputs are 1?
Answer: A
AND gate produces 1 only when all inputs are 1. For 2-input AND: output = A.B
Q.536Easy
What is the Boolean expression for XOR gate with inputs A and B?
Answer: B
XOR produces 1 when inputs are different: A⊕B = A.B' + A'.B
Q.537Easy
How many flip-flops are required to design a MOD-16 counter?
