Mechanical Engineering
GATE ME format:nat PYQs
Build your understanding with focused practice from past exam papers.
Questions 251–260 of 418. Imported answers require independent review unless marked reviewed.
Question 54
Open questionMENAT2 marksNeeds review
In a steam power plant, superheated steam at 10 MPa and 500°C, is expanded isentropically in a turbine until it becomes a saturated vapor. It is then reheated at constant pressure to 500°C. The steam is next expanded isentropically in another turbine until it reaches the condenser pressure of 20 kPa. Relevant properties of steam are given in the following two tables. The work done by both the turbines together is ______ kJ/kg (round off to the nearest integer).
Superheated Steam Table:
Pressure, (MPa) | Temperature, (°C) | Enthalpy, (kJ/kg) | Entropy, (kJ/kg.K) |
|---|---|---|---|
10 | 500 | 373.6 | 6.595 |
1 | 500 | 348.4 | 7.621 |
Saturated Steam Table:
Pressure, | Sat. Temp. (°C) | Enthalpy, (kJ/kg) | Enthalpy, (kJ/kg) | Entropy, (kJ/kg.K) | Entropy, (kJ/kg.K) |
|---|---|---|---|---|---|
1 MPa | 179.91 | 762.9 | 2778.1 | 2.1386 | 6.596 |
20 kPa | 60.06 | 251.38 | 2609.7 | 0.8319 | 7.9085 |
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 55
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The indicated power developed by an engine with compression ratio of 8, is calculated using an air-standard Otto cycle (constant properties). The rate of heat addition is 10 kW. The ratio of specific heats at constant pressure and constant volume is 1.4. The mechanical efficiency of the engine is 80 percent.
The brake power output of the engine is ______ kW (round off to one decimal place).
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Keeping all other parameters identical, the Compression Ratio (CR) of an air standard diesel cycle is increased from 15 to 21. Take ratio of specific heats = 1.3 and cut-off ratio of the cycle
.The difference between the new and the old efficiency values, in percentage,
______ % (round off to one decimal place).Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 18
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Evaluation of
using a 2-equal-segment trapezoidal rule gives a value of ________Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 19
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A block of mass 10 kg rests on a horizontal floor. The acceleration due to gravity is 9.81 m/s². The coefficient of static friction between the floor and the block is 0.2. A horizontal force of 10 N is applied on the block as shown in the figure. The magnitude of force of friction (in N) on the block is ______
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If
is the mean of data 3,
, 2 and 4, then the mode is ______Log in to check the answer
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A cylindrical rod of diameter 10 mm and length 1.0 m is fixed at one end. The other end is twisted by an angle of 10° by applying a torque. If the maximum shear strain in the rod is
, then p is equal to ______ (round off to two decimal places).Log in to check the answer
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The figure shows an idealized plane truss. If a horizontal force of 300 N is applied at point A, then the magnitude of the force produced in member CD is ______ N.
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A solid cube of side 1 m is kept at a room temperature of 32 °C. The coefficient of linear thermal expansion of the cube material is
/°C and the bulk modulus is 200 GPa. If the cube is constrained all around and heated uniformly to 42 °C, then the magnitude of volumetric (mean) stress (in MPa) induced due to heating is ______Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 21
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The state of stress at a point in a component is represented by a Mohr’s circle of radius 100 MPa centered at 200 MPa on the normal stress axis. On a plane passing through the same point, the normal stress is 260 MPa. The magnitude of the shear stress on the same plane at the same point is ______ MPa.
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