Q. 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.

View solution

Q. Current density has the dimensions

View solution

Q. 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

View solution

Q. The current in a circuit is measured using a 150 : 1 CT If the ammeter reads 0.6 A, the circuit current is

View solution

Q. A volt ratio box should have low resistance.

View solution

Q. 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

View solution

Q. 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

View solution

Q. Which of the following is not correct?

View solution

Q. Assertion (A): Thermocouple instruments can be used for ac only.

Reason (R): Thermocouple instrument has a non linear scale.

View solution

Q. A meter has a resistance of 1 Ω and full scale deflection current of 1 mA. To convert into an ammeter of 1 A range, the shunt resistance should be

View solution

Q. Two wattmeter method is suitable only for balanced loads.

View solution

Q. A rectifier voltmeter using bridge rectifier and PMMC meter is calibrated to read rms value of sine wave. A triangular wave is applied to it and it reads 6.82 V. The rms value of triangular wave is

View solution

Q. A radiation thermometer is suitable for temperatures

View solution

Q. A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is

View solution

Q. Wheatstone bridge is suitable for low resistances.

View solution

Q. To avoid creep in an energy meter

View solution

Q. A wire strain gauge has a gauge factor of 2, resistance of 125 Ω and length 1 m. If length of wire changes by .005 m, change in resistance will be

View solution

Q. Four voltmeters have following specifications. If accuracy is main consideration which is the best?

View solution

Q. The deflection of a DArsonval galvanometer is measured through a mirror and scale. The mirror is 1 m away from the light source. The mirror is mounted on, the moving system. If mirror rotates through 0.2 rad the displacement on the scale is

View solution

Q. Two ammeters having resistances of 0.5 Ω and 0.25 Ω and having full scale reading of 25 A each are connected in parallel. To ensure that neither of them goes beyond scale, the total current should not be more than

View solution