# Objective Questions on Mechanical Engineering

**25-The Full range form atmospheric pressure to a perfect vacuum is:**

(A) 7.14 Psi

(B) 0.40 Torr

(C) 14.7 Psi

(D) 0.40 Psi

**26-The difference between gauge and absolute pressure is:**

(A) Vacuum

(B) Atmospheric pressure

(C) Zero

(D) 0.433 Psi

**27-At shut off head of a centrifugal pump, the discharge is:**

(A) Maximum

(B) Zero

(C) Rated Discharge

(D) None

**28-Pelton wheel is used in those places where:**

(A) high head and low discharge are available

(B) low head and high discharge are available

(C) high head and high discharge are available

(D) none of the above

**29-Francis turbine is a**

(A) radial flow turbine

(B) axial flow turbine

(C) mixed flow turbine

(D) inward flow reaction turbine

**30-Critical thickness of insulation for a sphere with thermal conductivity ‘k’ and convective heat transfer coefficient ‘h’ is given by**

(A) 2k/h

(B) k/h

(C) k/4h

(D) k/2h

**31-The intensity of solar radiation on earth is:**

(A) 0.5 kW/m^{2}

(B) 1.3 kW/m^{2}

(C) 2.0 kW/m^{2}

(D) 5 kW/m^{2}

**32-The ratio of heat transfer by convection to that by conduction is called:**

(A) Stanton Number

(B) Nusselt Number

(C) Biot Number

(D) Peclet Number

**33-Which dimensionless number has a significant role in natural convection?**

(A) Grashof number

(B) Peclet Number

(C) Mach number

(D) None

**34-Optical Pyrometer working principle is based on**

(A) Stefan-Boltzmann law

(B) Weins displacement law

(C) Kirchoff law

(D) Planks law

**35-Peclet Number NPe is the product of**

(A) Reynolds number and Nusselt Number

(B) Reynolds number and Prandtl number

(C) Reynolds number and Rayleigh number

(D) Prandtl number and Nusselt number

**36-A U-tube manometer is connected to a vessel to measure the pressure inside. If mercury is the working fluid of manometer, the height difference between two columns of the manometer measured is 24 cm, the pressure inside the vessel in kPa is:**

(A) 31.9

(B) 49.1

(C) 3.1

(D) 10.4

**ANSWERS:**

**25-(C), 26-(B), 27-(B), 28-(A), 29-(D), 30-(A), 31-(B), 32-(B), 33-(A), 34-(D), 35-(B), 36-(A)**