Which one of the following is true for black body

- a)
- b)
- c)
- d)

Correct answer is option 'B'. Can you explain this answer?

DINESH GARG answered • 58 minutes ago

Since black body is perfect absorber of radiation hence absorptivity of black body α = 1.

Akshansh Sharma asked • 16 minutes ago

For the same indicated work per cycle, mean speed and permissible fluctuation of speed, what is the size of flywheel required for a multi-cylinder engine in comparison to a single cylinder engine?

- a)Bigger
- b)Smaller
- c)Same
- d)depends on thermal efficiency of the engine

Correct answer is option 'B'. Can you explain this answer?

A plate having 10 cm^{2} area each side is hanging in the middle of a room of 100 m^{2 }total surface area, the plate temperature and emissivity are respectively 800 K and 0.6. The temperature and emissivity values for the surface of the room are 300 K and 0.3 respectively. Boltzman’ constant σ = 5.67 x 10^{-8} W/m^{2}K^{4}. The total heat loss from the two surface of the plate is

- a)13.66 W
- b)27.32 W
- c)27.87 W
- d)13.66 MW

Correct answer is option 'B'. Can you explain this answer?

RAM AGARWAL answered • 58 minutes ago

A_{1} = 20 cm^{2} = 20 x 10^{-4}m^{2}

A_{2 }= 100 m^{2}

T_{1} = 800K

∈_{1 }= 0.6

T_{2 }= 300 K

∈_{2} = 0.3

A

T

∈

T

∈

Two long parallel surfaces each of emissivity 07 are maintained at different temperature and accordingly have radiation heat exchange between them. It is desirable to reduce 75% of this radiant heat transfer by inserting thin parallel shields of equal emissivity on both sides. The number of shields should be

- a)one
- b)two
- c)three
- d)four

Correct answer is option 'C'. Can you explain this answer?

GAJENDER SINGH answered • 58 minutes ago

where N = Number of radiation shield

An electronic device in the form of a wire is found to dissipate maximum heat when its outer most diameter = 32 mm. Keeping all the parameter same, it is proposed to use the same device in spherical form. The ideal diameter would be

- a)32 mm
- b)16 mm
- c)64 mm
- d)8 mm

Correct answer is option 'A'. Can you explain this answer?

SANDEEP SHAH answered • 58 minutes ago

Anuj Chauhan asked • 26 minutes ago

In the calculation of induced shear stress in helical springs, the Wahl's correction factor is used to take care of

- a)Combined effect of transverse shear stress and bending stresses in the wire.
- b)Combined effect of bending stress and curvature of the wire.
- c)Combined effect of transverse shear stress and curvature of the wire.
- d)Combined effect of torsional shear stress and transverse shear stress in the wire.

Correct answer is option 'C'. Can you explain this answer?

The thermal radiative flux from a surface of emissivity = 0 .4 is 22.68 kW /m^{2}. The approximate surface temperature (K) is

Stefan Boltzmann's constant = 5.67x10^{-8} W/m^{2}K^{4}

Stefan Boltzmann's constant = 5.67x10

- a)1000
- b)727
- c)800
- d)1200

Correct answer is option 'A'. Can you explain this answer?

ARUN KUMAR answered • 11 hours ago

We know, for radiation heat transfer

Udaygopal Kollikonda asked • 54 minutes ago

Carbonisation of coal is the process of

- a)enriching carbon in the coal
- b)strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel
- c)heating wood in a limited supply of air of temperatures below = 300°C
- d)pulverising coal in inert atmosphere

Correct answer is option 'B'. Can you explain this answer?

A composite wall of a furnace has 3 layers of equal thickness having thermal conductivities the ratio of 1 : 2 : 4. What will be the temperature drop ratio across the three respective layer

- a)1 : 2 : 4
- b)4: 2: 1
- c)1 : 1 : 1
- d)log 4 : log 2 : log 1

Correct answer is option 'B'. Can you explain this answer?

DEEPAK SHIVHARE answered • 11 hours ago

From the fourier law of heat conduction

Supantha Sarkar asked • 1 hour ago

Consider the following statements relating to hydraulic gradient line and energy gradient line:

1.In the case of a fluid flowing in a pipeline, hydraulic gradient line and energy gradient line may coincide.

2.The line joining the points representing piezometric heads is known as hydraulic gradient.

In the case of ideal fluid, energy gradient line is always horizontal.

3.Hydraulic gradient line has a downward slope in the case of flow through pipes.

Of these statements,

1.In the case of a fluid flowing in a pipeline, hydraulic gradient line and energy gradient line may coincide.

2.The line joining the points representing piezometric heads is known as hydraulic gradient.

In the case of ideal fluid, energy gradient line is always horizontal.

3.Hydraulic gradient line has a downward slope in the case of flow through pipes.

Of these statements,

The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is kW/m^{2}. The flux when the element temperature is increased to 1000°C for the same furnace temperature is

- a)11.2 kW/m
^{2} - b)12.0 kW/m
^{2} - c)14.6 kW/m
^{2} - d)16.5 kW/m
^{2}

Correct answer is option 'D'. Can you explain this answer?

MANOJ SHIVHARE answered • 11 hours ago

For radiation heat transfer

Devang Mathurekar asked • 1 hour ago

Decreasing grain size in a polycrystalline material

- a)Increases yield strength and corrosion resistance.
- b)Decreases yield strength and corrosion resistance
- c)Decreases yield strength but increases corrosion resistance
- d)Increases yield strength but decreases corrosion resistance.

Correct answer is option 'A'. Can you explain this answer?

For a circular tube of equal length and diameter shown below, the view factor F_{13} = 0.17. The view factor F_{12} in this case will be

- a)0.17
- b)0.21
- c)0.79
- d)0.83

Correct answer is option 'D'. Can you explain this answer?

RAM JHA answered • 11 hours ago

f_{11} + f_{12} + f_{13} = 1

f_{11} = 0

f_{12} = 1 - f_{13}

f_{12} = 1 - 0.17 = 0.83

f

f

f

A slab of thickness L with one side (x = 0) insulated and other side (x = L) maintained at a constant temperature T_{0} is shown below:

A uniformly distributed internal heat source produces heat in the slab at the rate of W/m^{3}. Assume the heat conduction to be steady state and 1 - D along the x-direction, the maximum temperature in the slab occurs at x equal to

A uniformly distributed internal heat source produces heat in the slab at the rate of W/m

- a)0
- b)L/4
- c)L/2
- d)L

Correct answer is option 'A'. Can you explain this answer?

DILPREET SINGH answered • 11 hours ago

For maximum temp, in the wall

Manish Patel asked • 1 hour ago

The concept of continuum in fluid flow assumes that the characteristics length of the flow is

- a)smaller than the mean free path of the molecules.
- b)larger than the mean free path of the molecule
- c)larger than the dimensions of the suspended particles
- d)larger than the wavelength of sound in the medium.

Correct answer is option 'B'. Can you explain this answer?

The radiative heat transfer rate per unit area (W/m^{2}) between two plane parallel grey surface (emissivity = 0.9) maintained at 400 K and 300 K is (StefanBoltzmann constant s = 5.67 x 10^{-8} W/m^{2}K^{4})

- a)1020
- b)464
- c)812
- d)567

Correct answer is option 'C'. Can you explain this answer?

NARESH DESHMUKH answered • 11 hours ago

Chandan Patel 007 asked • 2 hours ago

In carrying out a work sampling study in a machine shop, it was found that a particular lathe was down for 20% of the time. What would be the 95% confidence interval of this estimate if 100 observations were made?

- a)0.16, 0.24
- b)0.12, 0.28
- c)0.08, 0.32
- d)None of these

Correct answer is option 'B'. Can you explain this answer?

Chandan Patel 007 asked • 2 hours ago

A control chart is established with limits of ± 2 standard errors for use in monitoring samples of size n = 20. Assume the process to be in control. What is the likelihood of a sample mean falling outside the control limits?

- a)97.7%
- b)95.5%
- c)4.5%
- d)2.3%

Correct answer is option 'C'. Can you explain this answer?

Sreenath Narayandas asked • 4 hours ago

The hydro-state thrust bearing consists of six pads; each pad can be approximated as circular area of 500 mm and 100 mm as outer and inner diameters respectively. The total thrust load is 900 kN and film thickness is 0.05 mm and the viscosity of the lubricant is 58.86 cp.

Q.

Determine the supply pressure

- a)15.36 MPa
- b)1.11 MPa
- c)2.56 MPa
- d)6.67 MPa

Correct answer is option 'C'. Can you explain this answer?

Sermarani P asked • 4 hours ago

The essential condition for the transfer of heat from one body to another is.

- a)both bodies must be in physical contact
- b)heat content of one body must be more than that of the other
- c)one of the bodies must have a high value of thermal conductivity
- d)there must exist a temperature difference between the bodies

Correct answer is option 'D'. Can you explain this answer?

Sravani asked • 5 hours ago

Assertion (A): Rankine efficiency would approach Carnot cycle efficiency byproviding a series of regenerative feed heating.Reason (R): With regenerative feed heating, expansion through the turbine approaches an isentropic process.

- a)Both A and R are individually true and R is the correct explanation of A
- b)Both A and R are individually true but R is not the correct explanation of A
- c)A is true but R is false
- d)A is false but R is true

Correct answer is option 'B'. Can you explain this answer?

Hardik Barot asked • 7 hours ago

The standard specification of a grinding wheel is A-46=M-6-V-21. It means a wheel of

- a)Aluminum oxide of mesh size 6
- b)Boron carbide of mesh size 46
- c)Aluminum oxide of mesh size 46
- d)Silicon carbide of mesh size 6

Correct answer is option 'C'. Can you explain this answer?

Sagar Bansal asked • 7 hours ago

Two insulating materials of thermal conductivity K and 2K are available for lagging a pipe carrying a hot fluid. If the radial thickness of each material is the same.

- a)Material with higher thermal conductivity should be used for the inner layerand one with lower thermal conductivity for the outer.
- b)Material with lower thermal conductivity should be used for the inner layerand one with higher thermal conductivity for the outer.
- c)It is immaterial in which sequence the insulating materials are used.
- d)It is not possible to judge unless numerical values of dimensions are given.

Correct answer is option 'B'. Can you explain this answer?

Wasi Khan asked • 7 hours ago

Consider the following statements:

If at a section distant from one of the ends of the beam, M represents the bending moment. V the shear force and w the intensity of loading, then

1. dM/dx = V

2. dV/dx = w

3. dw/dx = y

(the deflection of the beam at the section)

Select the correct answer using the codes given below:

- a)1 and 3
- b)1 and 2
- c)2 and 3
- d)1, 2 and 3

Correct answer is option 'B'. Can you explain this answer?

Gnaneswar G asked • 7 hours ago

If cohesion between molecules of a fluid is greater than adhesion between fluid and glass, then the free level of fluid in a dipped glass tube will be

- a)higher than the surface of liquid
- b)the same as the surface of liquid
- c)lower than the surface of liquid
- d)unpredictable
- e)none of the above

Correct answer is option 'C'. Can you explain this answer?

Udit Agrawal asked • 8 hours ago

The value of heat and work transfer for the flow processes of a thermodynamic cycle are given below:

The thermal efficiency and work ratio for the cycle will be respectively

- a)33% and 0.66
- b)66% and 0.36
- c)36% and 0.66
- d)33% and 0.36

Correct answer is option 'B'. Can you explain this answer?

Aadarsh Vikram asked • 8 hours ago

Consider the following statements for a 4-cylinder inline engine whose cranks are arranged at regular intervals of 90°:

1. There are 8 possible firing orders for the engine.

2. Primary force will remain unbalanced for some firing orders.

2. Primary force will remain unbalanced for some firing orders.

Which of the statements given above is/are correct?

- a)1 only
- b)2 only
- c)Both 1 and 2
- d)Neither 1 nor 2

Correct answer is option 'D'. Can you explain this answer?

Alpesh Jain asked • 9 hours ago

Buyers products company distributes an item known as a tie bar, which is a U-bolt used on truck equipment. The following data have been collected for this item held in inventory.

Monthly demand forecast, d = 11,107 units

Monthly demand forecast, d = 11,107 units

Standard error of forecast = 3,099 units

Replenishment lead time, LT = 1.5 months

Item value, C = $ 0.11/unit

Cost for processing vendor order, S = $ 10/order

Carrying cost, I = 20%/year

In-stock probability during lead time,

P = 75% Find the reorder level

Vipin Kumar asked • 9 hours ago

The process of making hollow castings of non circular shape and desired thickness of non circular shape and desired thickness by permanent mould without use of core is known as

- a)die casting
- b)Slush casting
- c)Pressed casting
- d)Centrifugal casting

Correct answer is option 'B'. Can you explain this answer?

Bhushana Rao Kona asked • 9 hours ago

According to the law of moments, if a number of coplaner forces acting on a particle are in equilibrium, then

- a)their algebraic sum is zero
- b)their lines of action are at equal distances
- c)the algebraic sum of their moments about any point in their plane is zero
- d)the algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.

Correct answer is option 'C'. Can you explain this answer?

Achuth Kumar Yelleti asked • 10 hours ago

Assertion (A): If the bending moment along the length of a beam is constant, then the beam cross section will not experience any shear stress.

Reason (R): The shear force acting on the beam will be zero everywhere along the length.

- a)Both A and R are individually true and R is the correct explanation of A
- b)Both A and R are individually true but R is NOT the correct explanation of A
- c)A is true but R is false
- d)A is false but R is true

Correct answer is option 'A'. Can you explain this answer?

Rohan Pal asked • 10 hours ago

If a bearing is designated by the number 305, it means that the bearing is of

- a)light series whose bore is 5 mm
- b)light series whose bore is 25 mm
- c)medium series whose bore is 5 mm
- d)medium series whose bore is 25 mm

Correct answer is option 'D'. Can you explain this answer?

Achuth Kumar Yelleti asked • 11 hours ago

A beam having uniform cross-section carries a uniformly distributed load of intensity q per unit length over its entire span, and its mid-span deflection is δ.

The value of mid-span deflection of the same beam when the same load is distributed with intensity varying from 2q unit length at one end to zero at the other end is:

- a)1/3 δ
- b)1/2 δ
- c)2/3 δ
- d)δ

Correct answer is option 'D'. Can you explain this answer?

Abhishek Govil asked • 11 hours ago

In a vapour compression refrigeration system, throttle valve is used in place of an expander because

- a)it considerably reduces the system weight
- b)it improves the COP, as the condenser is small
- c)the positive work in isentropic expansion of liquid is very small
- d)it leads to significant cost reduction

Correct answer is option 'C'. Can you explain this answer?

Abhishek Govil asked • 11 hours ago

An elastic body is subjected to a tensile stress X in a particular direction and a compressive stressY in its perpendicular direction. X and Y are unequal in magnitude. On the plane of maximumshear stress in the body there will be

- a)no normal stress
- b)also the maximum normal stress
- c)the minimum normal stress
- d)both normal stress and shear

Correct answer is option 'D'. Can you explain this answer?

Pk Patel asked • 12 hours ago

Which one of the following statements is NOT true of rolling contact bearing?

- a)The bearing characteristic number is given by ZN/p where Z is the absolute viscosity of the lubricant, N is the shaft speed and p is the bearing pressure.
- b)Inner race of a radial ball bearing has an interference fit with the shaft and rotates along with it
- c)Outer race of the bearing has an interference fit with bearing housing and does not rotate
- d)In some cases, the inner race is stationary and outer race rotates

Correct answer is option 'D'. Can you explain this answer?

Navdeep Jadoun asked • 12 hours ago

Key concept in analyzing the filling of an evacuated tank is

- a)the mass flow rate in the tank remains constant
- b)the enthalpy across the valve remains constant
- c)the internal energy in the tank remains constant
- d)the temperature in the tank remains constant

Correct answer is option 'B'. Can you explain this answer?

Ankit Singh asked • 12 hours ago

Which of the following pattern-materials are used in Precision Casting?

1. Plaster of Paris

2. Plastics

3. Anodized Aluminium Alloy

4. Frozen Mercury

Select the correct answer using the codes given below:

- a)1 and 2
- b)2 and 4
- c)3 and 4
- d)1 and 3

Correct answer is option 'B'. Can you explain this answer?

Sai Teja asked • 12 hours ago

A round rod of annealed bras 70-30 is being drawn from a diameter of 8 mm to a diameter of 4 mm at a speed of 0.8 m/s. (k = 895 MPa, n = 0.49)

Q.

The power required in this operation is

- a)3.497 kW
- b)1.47 kW
- c)2.88 kW
- d)2.32 kW

Correct answer is option 'A'. Can you explain this answer?

SANDEEP SHAH asked • 12 hours ago

Air at 100 KPa and 280 K is compressed steadily to 600 KPa and 400 K. The mass flow rate of air is 0.02 Kg/s and a heat loss of 16 kJ/Kg occurs during the process. The power input to compressor will be_____kW

Correct answer is between '-2.730,-2.372'. Can you explain this answer?

Gokul Krishnan asked • 13 hours ago

Consider the following operations involved in forging a hexagonal bolt from a round bar stock, whose diameter is equal to the bolt diameter:

1. Flattening 2. Upsetting 3. Swaging 4. Cambering

1. Flattening 2. Upsetting 3. Swaging 4. Cambering

Q.

The correct sequence of these operations is

- a)1, 2, 3, 4
- b)2, 3, 4, 1
- c)2, 1, 3, 4
- d)3, 2, 1, 4

Correct answer is option 'A'. Can you explain this answer?

Amit Sharma asked • 13 hours ago

Consider the following statements: In the thermoelectric refrigeration, the coefficient of performance is a function of:

1. Electrical conductivity of materials

2. Pelti er coefficie nt

3. Seeb eck coefficie nt

4. Temperature at cold and hot junctions

5. Thermal conductivity of materials.

Of these statements:

[IES-1997]

- a)1, 3, 4 and 5 are correct
- b)1, 2, 3 and 5 are correct
- c)1, 2, 4 and 5 are correct
- d)2, 3, 4 and 5 are correct

Correct answer is option 'C'. Can you explain this answer?

Krishnendu Karmakar asked • 13 hours ago

and flat but are wavy. [IES-2003]

- a)Both A and R are true and R is the correct explanation of A
- b)Both A and R arc true but R is NOT the correct explanation of A
- c)A is true hut R is false
- d)A is false but R is true

Correct answer is option 'C'. Can you explain this answer?

Aadarsh Vikram asked • 13 hours ago

A compound cylinder with inner radius 5 cm and outer radius 7 cm is made by shrinking one cylinder on to the other cylinder. The junction radius is 6 cm and the junction pressure is 11 kgf/cm^{2}. The maximum hoop stress developed in the inner cylinder is

- a)36 kgf/cm
^{2}compression - b)36 kgf/cm
^{2}tension - c)72 kgf/cm
^{2}compression - d)72 kgf/cm
^{2}tension.

Correct answer is option 'C'. Can you explain this answer?

Saurav Chaturvedi asked • 13 hours ago

If two bodies having masses *m*_{1} and *m*_{2} (*m*_{1}>*m*_{2}) have equal kinetic energies, the momentum of body having mass *m*_{1} is __________ the momentum of body having mass *m*_{2}.

- a)equal to
- b)less than
- c)greater than

Correct answer is option 'C'. Can you explain this answer?

Nilutpal D. asked • 13 hours ago

A manufacturer's master product schedule of a product is given below:

Each product requires a purchased component A in its subassembly. Before the start of week-1, there are 400 components of type A in stock. The lead time to procure this component is 2 weeks and the order quantity is 400. Number of components A per product is only one. The manufacturer should place the order for

Kamal Bhardwaj asked • 13 hours ago

Assertion (A): The degree of hunting with an unstable governor will be less than with an isochronous governor.

Reason (R): With an unstable governor, once the sleeve has moved from one extreme position to the other, a finite change of speed is required to cause it to move back again.

- a)Both A and R are individually true and R is the correct explanation of A
- b)Both A and R are individually true but R is not the correct explanation of A
- c)A is true but R is false
- d)A is false but R is true

Correct answer is option 'A'. Can you explain this answer?

Pooja Shende asked • 14 hours ago

Air is being forced by the bicycle pump into a tyre against a pressure of 4-5 bars. A slow downward movement of the piston can be approximated as

- a)Isobaric process
- b)Adiabatic process
- c)Throttling process
- d)Isothermal process

Correct answer is option 'D'. Can you explain this answer?

Sandip Mangal asked • 14 hours ago

Consider the following quenching media:

1. Oil

2. Water

3. WaterNaOH

4. Brine

1. Oil

2. Water

3. WaterNaOH

4. Brine

The correct sequence of these media in order of increasing hardness of steel under going heat treatment is

- a)1, 3, 2, 4
- b)2, 1, 3, 4
- c)1, 2, 3, 4
- d)none

Correct answer is option 'C'. Can you explain this answer?

Anunay Prasanna asked • 14 hours ago

The given diagram shows an isometric cooling process 1–2 of a pure substance. The ordinate and abscissa are respectively

- a)Pressure and volume
- b)Enthalpy and entropy
- c)Temperature and entropy
- d)Pressure and enthalpy

Correct answer is option 'D'. Can you explain this answer?

Pooja Shende asked • 14 hours ago

A 400 mm diameter shaft is rotating at 200 rpm in a bearing of length 120 mm. If the thickness of oil film is 1.5 mm and the dynamic viscosity of the oil is 0.7 Ns/m^{2} determine:

(i) Torque required overcoming friction in bearing;

(ii) Power utilization in overcoming viscous resistance;

(i) Torque required overcoming friction in bearing;

(ii) Power utilization in overcoming viscous resistance;

Correct answer is 'Ans. (i) 58.97 Nm (ii) 1.235 kW'. Can you explain this answer?

Dharani Kumar asked • 14 hours ago

Two blocks of iron and copper, both initially at 80^{0}C, are dropped into a large lake at 15^{0}C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.

Total entropy change for this process is:-

C_{iron} = 0.45 kJ/kg^{0}C, C_{copper} = 0.386 kJ/kg^{0}C

C

- a)-4.579 kJ/K
- b)-1.571kJ/K
- c)0.670 kJ/K
- d)6.820 kJ/K

Correct answer is option 'C'. Can you explain this answer?

Keshav Galav asked • 14 hours ago

An insulated tank contains 120L of water at 25^{0}C ( ρ = 997 kg/m^{3}, C_{P} = 4.18 kJ/kg^{0}C). A 50kg copper block (C_{P} = 0.386 kJ/kg^{0}C) initially at 80^{0}C is dropped into water. Total entropy change for this process will be:-

- a)3.344 kJ/K
- b)0.204 kJ/K
- c)3.104 kJ/K
- d)6.448 kJ/K

Correct answer is option 'B'. Can you explain this answer?

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