1. What will be the thermal stress developed in a rod having a diameter of 4 cm and length of 2 m. It experiences heating from temperature 50°C to 200°C. The coefficient of thermal expansion is a = 10 x 10^-6° / °C and young's modulus is 250 GPa ?

300

325

350

375

Answer: 375

Explanation:


2. Which of the following is a dimensionless quantity ?

Shear stress

Poisson's ratio

Torque

None of these

Answer: Poisson's ratio

Explanation:


3. What will be the value of Poisson’s ratio,if the elasticity and rigidity of the material is 200 GPa and 66.67 GPa ?

0

0.25

0.5

1

Answer: 0.5

Explanation:


4. What will be the dryness fraction for liquid (m1) and vapour (m2) mixtureWhat will be the dryness fraction for liquid (m1) and vapour (m2) mixture ?

x= (m1+m2)/m1

x= m2/(m1+m2)

x= (m1+m2)/m2

x= m1/(m1+m2)

Answer: x= m2/(m1+m2)

Explanation:


5. What is the amount of maximum work that can be extracted from a Carnot engine working between temperature 1000 K and 100 K ?

0.1

0.5

0.9

0.99

Answer: 0.9

Explanation:


6. When the degree of randomness increases, what is the change in entropy ?

Decreases

Increases

Unpredictable

Remains constant

Answer: Increases

Explanation:


7. Which entropy value best defines the state of water at triple point ?

Zero

More than zero

Less than zero

None of these

Answer: Zero

Explanation:


8. Which of the following cycle is used in compression ignition (SI) engine ?

Carnot cycle

Diesel cycle

Dual cycle

Otto cycle

Answer: Diesel cycle

Explanation:


9. The self ignition temperature of diesel is .......... as compared to that of petrol ?

is higher

is lower

is same

cannot be determined

Answer: is lower

Explanation:


10. What happens when supercharging is done for spark ignition engines ?

Increase knocking

Decrease knocking

No effect

May increase or decrease

Answer: Increase knocking

Explanation: