# GATE Mechanical Engineers Don’t Want You to See These 37 Questions and Answers!

GATE (Graduate Aptitude Test in Engineering) is one of the most popular exams for Engineering graduates in India. It tests the comprehensive understanding of various undergraduate subjects in Engineering.

The GATE Mechanical Engineering paper tests the conceptual knowledge and analytical abilities of students in major areas like Engineering Mechanics, Strength of Materials, Theory of Machines, Machine Design, Fluid Mechanics, Thermodynamics, Heat Transfer, Materials Engineering, Manufacturing Processes, Industrial Engineering etc.

Based on analysis of previous years’ papers and experiences shared by toppers, here are some of the most frequently asked questions and their answers in GATE Mechanical Engineering exam:

1. In a four-stroke petrol engine, the valves open and close how many times per cycle?

Ans: Intake valve opens twice and exhaust valve opens twice per cycle. So total 4 times.

1. During adiabatic process in an ideal gas, which property remains constant?

Ans: Entropy

1. What is the critical Reynolds number for flow through a pipe?

Ans: 2300

1. In a closed cycle, heat supplied to the system is equal to?

Ans: Net heat transfer i.e. Heat supplied – Heat rejected

1. What is the effect of increasing blade angle on the air screw characteristics?

Ans: It increases thrust and torque while decreasing efficiency

1. In a belt drive, if the belt starts slipping, which of the following tension remains unchanged?

Ans: Centrifugal tension

1. Splines are used to transmit power between:

Ans: Two parallel shafts

1. In a turning operation on lathe, the cutting speed increases if?

Ans: Depth of cut decreases

1. In facilitated diffusion across a membrane, solute transport happens:

1. In a simply supported beam with a point load at the center, maximum bending stress occurs at:

1. Hydrostatic force on a vertical plane surface submerged in liquid will be?

Ans: Equal to product of area, depth and density of liquid

1. Who proposed the theory of elasticity?

Ans: Hooke

1. Poisson’s ratio for rubber is close to?

Ans: 0.5

1. Governors are used to regulate:

Ans: Speed of engine shaft

1. Thermodynamic cycle in which heat addition and rejection take place at constant volume is?

Ans: Joule cycle

1. In a spring-mass system undergoing free vibrations, as damping increases, which of following decreases?

Ans: Amplitude

1. During adiabatic compression in a reciprocating compressor, work done on the gas is used to?

Ans: Increase its internal energy

1. The angle between velocity and acceleration of a particle executing SHM is:

Ans: 90 degrees

1. In a closed cycle, increase in internal energy is equal to:

Ans: Net heat added to the system

1. In a rectangular beam, maximum shear stress occurs at:

Ans: Neutral axis

1. Refrigeration effect is highest for which of the following refrigerants?

Ans: Ammonia

1. Force analysis is based on which law?

Ans: Newton’s second law

1. Reciprocating pumps are suitable for:

Ans: High pressure and low discharge applications

1. Efficiency of a perfect heat engine operating between 227°C and 127°C will be:

Ans: 0.5

1. Power transmitted by a shaft is maximum when:

Ans: Torque is maximum

1. In a closed cycle, increase in entropy is equal to:

Ans: Entropy transfer by heat addition

1. Material used for making gears is:

Ans: Cast iron

1. Cavitation in pumps can cause:

Ans: Damage to impeller and casing

1. Ratio of actual power output to theoretical power output in an IC engine is called:

Ans: Efficiency

1. Boyle’s law relates:

Ans: Pressure and Volume of gas at constant temperature

1. Types of fluid flow based on variation of flow velocity across pipe section are:

Ans: Laminar and Turbulent

1. Welding process used to join non-ferrous materials is:

Ans: Gas welding

1. In projectile motion under gravity, the path followed by the projectile is a:

Ans: Parabola

1. Fourier number represents:

Ans: Ratio of heat conduction rate to heat storage rate

1. Slenderness ratio of a column is:

Ans: Effective length/Least radius of gyration

1. Hydraulic turbines convert:

Ans: Potential energy of water into mechanical energy

1. Second law of thermodynamics deals with:

Ans: Direction of natural processes

## Conclusion

This covers some of the most frequently asked questions from major topics in the GATE Mechanical Engineering exam. Preparing these questions and understanding the concepts thoroughly will help you perform well in the exam. All the best!