127. Which of the following is not correct in respect of electrostatic instrument?
128. The wave applied to X plates, for ohtaining trace of voltage wave, is
129. The response of a thermistor overs the whole of its temperatures range is
130. A resistance is measured by voltmeter-ammeter method. The voltmeter is 0-250V, ± 1% accuracy and ammeter is 0-5 A, ± 1 % accuracy. The readings of voltmeter and ammeter are 100 V and 2 A respectively. The error in the measured resistance can be
131. It is required to study transients during switching process. Which CRO should be preferred?
132. Assertion (A): In loss of charge method, it is preferable to use an electronic voltmeter.Reason (R): The resistance of electronic voltmeter is very high.
133. If the secondary winding of CT is opened when primary coil is carrying current
134. The percentage limiting error in an instrument reading 8.3 V and having guaranteed accuracy of 1% of the full scale reading and range of 0-150 V is
135. Assertion (A): Thermocouple instruments can be used for ac only. Reason (R): Thermocouple instrument has a non linear scale.
136. 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
137. Two wattmeter method is suitable only for balanced loads.
138. 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
139. A radiation thermometer is suitable for temperatures
140. Consider the following statements Thermistor is more sensitive than platinum resistance thermometerThe resistance of thermistor is solely a function of its absolute temperature whether the source of heat is external or internalThermistor has linear temperature-resistance relationshipThermistor has linear negative temperature coefficient Of the Statements, the correct statements are
141. A moving coil meter has 10 Ω resistance and requires 40 mA for full scale deflection. The shunt resistance required to convert it into 0-2 A ammeter is
142. Which of the following instruments can be used for dc as well ac upto a few MHz? Moving iron instrumentThermocouple instrumentInduction instrumentMoving coil instrument Select the correct answer as per following codes
143. Assertion (A): Strain measurement using strain gauge invariably requires a dummy strain gauge.Reason (R): The resistance of strain gauge depends on temperature.
144. If a shunt of 200 Ω resistance is used with a galvanometer of 1000 Ω resistance, the multiplying power is
145. A 1 mA meter is to be converted to 1 A ammeter. The meter resistance is 100 Ω. The value of shunt resistance is
146. The use of thermocouple meters for ac measurement leads to a scale which is
147. Assertion (A): A low power factor wattmeter has special constructional features to ensure accurate measurement.Reason (R): Extension of wattmeter range in dc circuit can be easily done by using current and potential transformer.
148. The scale of dynamometer wattmeter is non linear.
149. Magnetic deflection is inversely proportional to
150. The most commonly used moving iron instruments are