Practice Pakistan's most useful MCQs for competitive exams

If response of a control system is to be free of offset and oscillation, the most suitable controller is_________________?

• (A)  Proportional controller
• (B)  Proportional-derivative (PD) controller
• (C)  Proportional-integral (PI) controller
• (D)  Proportional integral-derivative (PID) controller

Answer

Submitted By :Ali Uppal

For two non-interacting first order systems connected in series, the overall transfer function is the ______________ of the individual transfer functions?

• (A)  Product
• (B)  Ratio
• (C)  Sum
• (D)  Difference

Answer

Submitted By :Ali Uppal

Which of the following thermocouples is capable of measuring a temperature of -50°C ?

• (A)  Platinum-platinum + rhodium
• (B)  Chromel-Alumel
• (C)  Iron-constantan
• (D)  Copper-constantan

Answer

Submitted By :Ali Uppal

Reference points i.e., ice point and steam point in Reaumer temperature scale are respectively_________________?

• (A)  – 273° & 80°
• (B)  0° & 80°
• (C)  32° & 460°
• (D)  32° & 80°

Answer

Submitted By :Ali Uppal

Ordinary mercury in glass thermometer is used for measuring temperature upto 120°C. However, for measuring higher temperature upto __________ °C, thermometer is made by filling nitrogen under pressure above the mercury, which stops the evaporation of mercury and reduces the chance of broken thread of mercury?

• (A)  250
• (B)  350
• (C)  550
• (D)  700

Answer

Submitted By :Ali Uppal

Pyrometry refers to the measurement of temperature_________________?

• (A)  With the mercurial thermometer upto 350°C
• (B)  Directly
• (C)  Which is of higher magnitude
• (D)  All

Answer

Submitted By :Ali Uppal

Which of the following is not suitable for measuring the temperature of a red hot object in the range of 800 – 1600°C ?

• (A)  Optical pyrometer
• (B)  Radiation pyrometer
• (C)  Photoelectric pyrometer
• (D)  Thermocouples

Answer

Submitted By :Ali Uppal

Water is flowing through a series of four tanks and getting heated as shown in figure. It is desired to design a cascade control scheme for controlling the temperature of water leaving the tank 4 as there is a disturbance in the temperature of a second stream entering the tank 2. Select the best place to take the secondary measurement for the second loop?

• (A)  Tank 1
• (B)  Tank 2
• (C)  Tank 3
• (D)  Tank 4

Answer

Submitted By :Ali Uppal

A first order system with unity gain and time constant η is subjected to a sinusoidal input of frequency w = 1/η. The amplitude ratio for this system is______________?

• (A)  1
• (B)  0.5
• (C)  1/√2
• (D)  0.25

Answer

Submitted By :Ali Uppal

Silver point temperature is ______________ °C?

• (A)  760.5
• (B)  860.5
• (C)  960.5
• (D)  1060.5

Answer

Submitted By :Ali Uppal