For effective operation the strain gauge material should have a low value of
Gauge factor
Temperature sensitivity
Nominal resistance
Yield point and endurance limit
Which of the following gauges can be detached from the test specimen and used again?
Metal foil gauge
Semi-conductor gauge
Bonded metal wire gauge
Unbonded metal wire gauges
For a doped crystal, the gauge factor lies I the range
1-2
5-15
20-50
100-200
In semi conductor strain gauge the change in the value of resistance occurs primarily due to change in
Length only
Cross-sectional area only
Length as well as cross-sectional area
Resistivity of the strain gauge material
The use of semi-condctor strain gauges is limited due to their
Low frequency response
Low value of gauge factor
Poor linerarity and sensitivity to temperature changes
Small size and high cost auxiliary equipment
Which of the following materials is used as the carrier with strain gauge at room temperature?
Rubber
Epoxy resin
Bakelite
Impregnated paper
The bridge constant (sensitivity) of a half-bridge arrangement where two strain gauges suffer equal and opposite strains is
Unity
Doubled
Quadrupled
(1 x ) times
The use of a dummy strain gauge in a wheatstone bridge circuit helps to
Increase the sensitivity of the measuring instrument
Measure lateral strain
Eleiminate the errors due to variation in ambient temperature
Improve the stability of the system.
When measuring pure torsion, the strain gauges are bonded to the shaft
In the direction of the applied torque
Longitudinally along the shaft axis
Transversely to the shaft axis
At 45-degree to the axis of rotation
A strain bridge circuit is usually calibrated by
Applying known mechanical strain to the active gauge
Applying known voltage across thea active gauge
Shunting known resistance across the active gauge
Heating the active strain gauge to a known temperature
Which mode of electrical circuit is employed for the measurement of dynamic strain?
Null balance wheatstone bridge
Voltage sensitive deflection mode of wheatstone bridge
Current sensitive deflection mode of wheatstone brodge
Voltage sensitive potentiometric circuit.
Which parameter of dynamic input signal is generally determined by Lissajou diagram on an oscilloscope?
Frequency
Amplitude
Damping factor
Harmonic content
The average rotational speed measurements are made by
Centrifugal tachometer
Stroboscope
Revolution counter and timer
Drag cup tachometer
Identify the instrument that indicates the rotational speed of a shaft in revolutions minute
Tachometer
Tachoscope
Hand speed indicator
Odometer
Tachometers are used to measure
Displacement
Angular velocity
Acceleration
Vibration amplitude
The rotational speed of ths sealed compressor unit of a refrigerator can be measured by a
Stroboscope
Tachoscope
Vibrating reed tachometer
Capacitive pick-up tachometer
The stroboscopic method of speed measurement has the advantage that
The method is simple and straight forward
The multiples of angular speed can be measured
A stationary image can be measured
There is no need of any physical contact between the instrument and rotating shaft
A prony brake dynamometer measusres the
Crankshaft force
Crankshaft torque
Engine brake power
Power input to a pump
Froude’s absorption dynamometer is a
Transmission dynamometer
Mechanical friction dynamometer
Torsion dynamometer
Vortex type hydraulic dynamometer
Identify the transmission dynamometer
Eddy current dynamometer
Froude’s hydraulic dynamometer
Belt dynamometer
Electric cradled dynamometer