61551. A 24 mm long conductor has a resistance of 128 Ω. The change in resistance is 13.3 Ω and change in length is 1.6 mm under tension. The gauge factor is
61552. Measuring of unknown voltage with a dc potentiometer loses its advantage of open circuit measurement when
61553. In a digital measuring device the input electrical signal is in the frequency range of dc to ac (50) Hz. It must be sampled at a rate of
61554. A meter has a square law scale. For 2 A current the deflection in 90°. For a deflection of 45°, the current is
61555. Consider the following Statements regarding resistance strain gauge The gauge factor is in the range of 2 to 5.The resistance changes due to change in specific resistance with strain.The resistance increases with increase in temperature. Of the above statements, which are correct?
61556. PCM employing 4 bit code is used to send data having frequency range from 0 to 2 kHz. The minimum required bandwidth of carrier channel is
61557. A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in reverse direction. The reading on hot wire ammeter will be
61558. When a capacitor is connected to the terminals of an ohmmeter, the pointer indicated a low resistance initially and finally come to infinity position. This shows that capacitor is
61559. If eddy current damping is to be used, the disc of instrument should be
61560. The scale of moving iron instrument is linear.
61561. With a variable reluctance tachometer having 60 rotor teeth the count reads 3600 counts per minute. The speed in RPM is
61562. When measuring phase angle between two waves using a CRO, the time base generator is connected to
61563. It is required that a strain gauge has gauge factor of 100. The proper strain gauge is
61564. A meter having 0-1000 μA range and 1000 Ω resistance is required to be changed to 0-100 mA meter. The value of shunt resistance is about
61565. An induction wattmeter can be used for
61566. In the balanced bridge shown in figure. X should be
61567. If the current in a capacitor leads the voltage by 80°, the loss angle of capacitor is
61568. In an induction wattmeter, the shading bands are made of non conducting material.
61569. The current in a circuit is measured using a 150 : 1 CT If the ammeter reads 0.6 A, the circuit current is
61570. A volt ratio box should have low resistance.
61571. A Hall effect transducer has KH = - 1 x 10-8. If B = 1 Wb/m2, I = 3 A and bismuth slab is 2 mm wide, the Hall voltage is
61572. Two ammeters A and B both 0-10 A have internal resistance of 1 Ω and 0.5 Ω respectively. They are connected in parallel. If total current is 15 A, then
61573. A 3-ohm resistor is connected is parallel to 6-ohm resistor.The combination is connected in series to an 8-ohm resistor.A 10-ohm resistor is connected in parallel to the whole combination.The effective resistance is:
61574. The loss of charge method can be used to measure
61575. Assertion (A): Maxwell bridge is for measuring inductance of medium magnitude.Reason (R): In Maxwell's bridge the unknown inductance is measured by comparing it with a capacitance.
61576. Assertion (A): A semiconductor strain gauge is more accurate than a resistance strain gauge.Reason (R): The gauge factor of a semiconductor strain gauge is about 100 where as the gauge factor of a resistance strain gauge is only about 2.
61577. Current density has the dimensions
61578. The resistance of a dc galvanometer is 20 Ω. A current of 10 mA causes full scale deflection. To convert it into 0-300 V voltmeter, we have to use a series resistance of
61579. A capacitance transducer can be used to measure
61580. The dynamometer principle can be used for
61581. Assertion (A): In hot wire instrument the material of hot wire in generally platinum iridium.Reason (R): A hot wire ammeter is suitable for ac only
61582. The scale of hot wire ammeter is
61583. A moving coil meter has a shunt of 0.02 Ω resistance. If coil resistance is 1000 Ω and a potential difference of 500 mV is required across it to cause full scale deflection, the current through shunt is
61584. Consider the following features of an instrument suitable for both ac and dcfree from hysteresis and eddy current errorsNo waveform and frequency errorsit is essentially a voltmeter This instrument is
61585. Which one of the following effects is used in measuring power?
61586. The effect of lead resistance is important in measurement of
61587. A high resistance was measured by loss of charge method. The voltmeter resistance was 1010 ohms. The calculation gave the value of unknown resistance as 0.8 x 109 ohms. The true value of resistance is
61588. A resistance wire strain gauge has gauge factor 2. If stress is 100 mega newton/m2 and Young's modulus is 200 giga newton/ m2, the percentage change in gauge resistance due to stress is
61589. Insertion of a dielectric material between the plates of an air capacitor
61590. Two ammeters A and B are connected in parallel in a circuit carrying 100 A. Their resistances are 0.8 mΩ. Their readings will be.
61591. In figure, Za = 100∠50°, Zb = 300∠-90° and Zc = 200∠0°. For balanced condition, Zd will be
61592. In household energy meters the flux of series magnet is in phase with current but the flux of shunt magnet lags the voltage by 88°. The reading of energy meters
61593. Assertion (A): A universal RLC bridge has a battery and also a high frequency ac source.Reason (R): RLC bridge uses a Wienbridge arrangement for measuring capacitance.
61594. The emf of a Weston cell is 1.286 V.
61595. The power factor of a single phase load can be calculated if instruments available are
61596. A variable reluctance type tachometer has 150 teeth on rotor. The counter records 13500 pulse/sec. The rotational speed is
61597. The current through the coil of an electromagnet is doubled. The magnetic field around the coil
61598. In a moving iron voltmeter the coil has a resistance of 20 Ω and an inductance of 0.3 H. The swamping resistance in 2000 Ω. To ensure correct reading with dc as well as 50 Hz ac, the value of capacitor to be connected in parallel with swamping resistance should be
61599. Two resistances R1 = 18.7 Ω. and R2 = 3.624 Ω in series. The total resistance to the appropriate number of significant figures is