MAULANA AZAD NATIONAL INSTITUTE OF TECHNOLOGY, BHOPAL
Department of Electrical Engineering
B. Tech. III Semester
Sub: Measurement and Instrumentation (EE-24214)
Assignment - 1
Submission deadline: 14.08.2025
Q.1. An oscilloscope having an input resistance of 1MΩ shunted by 50pF capacitance is
connected across a circuit having an effective output resistance of 10kΩ. If the open
circuit voltage has 1V peak for 100kHz sine wave, what will be the voltage indicated
in the oscilloscope when the frequency is (i) 100kHz and (ii) 1MHz?
Q.2. What is the true value of the current in the 15kΩ resistor of the Fig.1. If an ammeter
of 2 kΩ is used to measure the current in 15kΩ resistor, what will it read? If an loading
accuracy of 99 percent is desired in measuring the current, what should the ammeter
resistance be?
Fig 1
Q.3. The losses in a motor are calculated by measuring the input and output power of the
motor and then taking the difference. In a particular motor, the input is measured as
6250W ±2% and the output is 5000W ±3%. The errors are limiting errors. Calculate
the losses and their percentage limiting error. Comment upon the results.
Q.4. Three resistors have the following ratings: R1 = 200Ω ± 5%, R2 = 100Ω ± 5%, R3 =
50Ω ± 5%. Determine the magnitude of resultant resistance and the limiting errors in
percentage and in ohm, if the three above resistors above connected in (i) series and
(ii) parallel.
Q.5. The power factor of a circuit is determined by cosϕ = VI / P, where P is the power in
watt, I the current in ampere and V the voltage in volt. The relative errors in power,
current and voltage are respectively ±0.5%, ±1% and ±1%. Calculate the relative error
in power factor. Also calculate uncertainty in the power factor if the errors were
specified as uncertainties.
Q.6. A 150Ω±10% resistor is connected to the terminals of a power supply operating at
200V±0V. What range of current would flow if the resistor varies over the range of
±10% of its expected value? What is the range of error in the current?
Q.7. Q7 A resistor is measured by the voltmeter-ammeter method. The voltmeter reading
is 123.4V on the 250V scale and the ammeter reading is 283.5mA on the 500mA scale.
Both meters are guaranteed to be accurate within ±1 percent of full-scale reading.
Determine: (a) the indicated value of the resistor; (b) the limits within which the result
can be guaranteed.
Q.8. The stress in a rod used for circular diaphragms is given as:
3𝐷2 𝑝
𝑠= 𝑁/𝑚2
16𝑡 2
where D and t are respectively diameter and thickness in diaphragm in mm and p is
the applied pressure in N/m2. A diaphragm has a diameter of 15mm, thickness of
0.2mm and is subjected to a pressure of 300x103 N/m2. Calculate the stress. The
known error in diameter is ±1%, and in the thickness is ±3%. Calculate the error in
the stress.
Q.9. The true value of voltage across a resistor is 50V. The measurement finds a value of
49V. Calculate (a) the absolute error (b) the percentage error and (c) the percentage
accuracy.
Q.10. A 0-100V voltmeter has 200 scale divisions which can be read to ½ division.
Determine the resolution of the meter in volt.
