Practice Pakistan's most useful MCQs for competitive exams

Which of the following measurements can be made by the measurement of emf ?

• (A)  pH value
• (B)  Degree of hydrolysis
• (C)  Composition of complex ions
• (D)  All

Answer

Submitted By :Ali Uppal

Sub-zero temperature (< 0°C) can be measured by a constant volume gas thermometer employing ?

• (A)  Helium
• (B)  Nitrogen
• (C)  Hydrogen
• (D)  None of these

Answer

Submitted By :Ali Uppal

Specific conductance is defined as the reciprocal of resistance in ohms of 1c.c. of liquid at a specified temperature. Its value for distilled water is about ______________ micro mho/cm3?

• (A)  50
• (B)  100
• (C)  10
• (D)  1

Answer

Submitted By :Ali Uppal

An ideal PID controller has the transfer function [1 + (1/0.55) + 0.25]. The frequency at which the magnitude ratio of the controller is 1, is________________?

• (A)  0.5/0.2
• (B)  0.2/0.5
• (C)  0.2 × 0.5
• (D)  1/√(0.2 × 0.5)

Answer

Submitted By :Ali Uppal

Phase lag of the frequency response of a second order system to a sinusoidal forcing function______________?

• (A)  Is 30°
• (B)  Is 90° at the most
• (C)  Approaches 180° asymptotically
• (D)  Is 120°

Answer

Submitted By :Ali Uppal

Which of the following is an undesirable dynamic characteristic of an instrument ?

• (A)  Reproducibility
• (B)  Dead zone
• (C)  Time lag
• (D)  Static error

Answer

Submitted By :Ali Uppal

Temperature control of an exothermic chemical reaction taking place in a CSTR is done with the help of cooling water flowing in a jacket around the reactor. The types of valve and controller action to be recommended are________________?

• (A)  Air to open valve with the controller direct acting
• (B)  Air to close valve with the controller indirect acting
• (C)  Air to open valve with the controller indirect acting
• (D)  Air to close valve with the controller direct acting

Answer

Submitted By :Ali Uppal

Thermal well made of _____________ gives the fastest speed of response, while measuring temperature by thermocouples?

• (A)  Steel
• (B)  Vycor (a glass)
• (C)  Nichrome
• (D)  Inconel

Answer

Submitted By :Ali Uppal

With increase in temperature, the electrical conductivity of the platinum used in the resistance thermometer ?

• (A)  Increases
• (B)  Decreases
• (C)  Remain constant
• (D)  Increases exponentially

Answer

Submitted By :Ali Uppal

For measuring the temperature of a red hot furnace, which is the most suitable instrument ?

• (A)  Platinum resistance thermometer
• (B)  Thermocouple
• (C)  Optical pyrometer
• (D)  Bimetallic thermometer

Answer

Submitted By :Ali Uppal