Practice Pakistan's most useful MCQs for competitive exams

Working principle of bimetallic thermometers is difference in linear co-efficient of thermal expansion of two strips of different metals welded together. Which of the following has the maximum thermal co-efficient of linear expansion ?

• (A)  Nickel
• (B)  Brass
• (C)  Chromel
• (D)  Invar

Answer

Submitted By :Ali Uppal

The characteristic equation for the control system with a closed loop transfer function G1/1 + G2 is given by 1 + G2 = 0. The characteristic equation for the control system_________________?

• (A)  Depends only upon the open loop transfer function
• (B)  Determines its stability
• (C)  Is the same for set point or load changes
• (D)  All A , B &

Answer

Submitted By :Ali Uppal

Response of a system to a sinusoidal input is called _____________ response?

• (A)  Impulse
• (B)  Unit step
• (C)  Frequency
• (D)  None of these

Answer

Submitted By :Ali Uppal

Polarograph is meant for the analysis of __________________?

• (A)  Gaseous mixture
• (B)  Miscible liquids
• (C)  Solids
• (D)  Isotopes

Answer

Submitted By :Ali Uppal

Use of I-control along with P-control facilitates ?

• (A)  Elimination of offset
• (B)  Reduction of offset
• (C)  Reduction of stability time
• (D)  None of these

Answer

Submitted By :Ali Uppal

Which of the following thermocouples will give the highest output for the same value of hot and cold junction temperature ?

• (A)  Platinum-platinum + rhodium
• (B)  Iron-constantan
• (C)  Chromel-constantan
• (D)  All will give the same output

Answer

Submitted By :Ali Uppal

For a feed back control system to be stable, the _________________?

• (A)  Roots of the characteristic equation should be real
• (B)  Poles of the closed loop transfer function should lie in the left half of the complex plane
• (C)  Bode plots of the corresponding open loop transfer function should monotonically decrease
• (D)  Poles of the closed loop transfer function should lie in the right half of the complex plane

Answer

Submitted By :Ali Uppal

The ____________ of the fluid contained in the temperature sensing element (i.e., bulb) of filled system thermometers changes with change in temperature ?

• (A)  Pressure
• (B)  Volume
• (C)  Viscosity
• (D)  All

Answer

Submitted By :Ali Uppal

Thermistor, which has high temperature co-efficient of resistivity, is used as the sensing element in resistance thermometer. It is a/an ?

• (A)  Insulator
• (B)  Conductor
• (C)  Solid semi-conductor
• (D)  Liquid semi-conductor

Answer

Submitted By :Ali Uppal

Thermistors are used in ____________ devices?

• (A)  Voltage measuring
• (B)  Temperature measuring
• (C)  Temperature compensating
• (D)  Both

Answer

Submitted By :Ali Uppal