Bissoy.com
Doctors Medicines MCQs Q&A

Related Questions

The largest size of immobilised segment of dislocation in a Frank Read (FR) source contained in a polycrystalline material is of the order of grain size. In a metal of 10 μm grain size, the shear stress required to operate such a FR source is 100 MPa. If the grain size in the same metal is reduced to 10 μm, the shear stress required to operate such FR source would be . . . . . . . . MPa.
A wave is first reflected by a boundary P and then by a boundary Q without dissipating energy. If the boundary P is rigid and the boundary Q is non-rigid, then find the fraction of the amplitude of the reflected wave by boundary P to the reflected wave by boundary Q.
The yield strenght of a polycrystalline metal increases from 100 MPa to 145 MPa on decreasing the grain size from 64 μm to 25 μm. The yield strenght of this metal (in MPa) having a grain size of 36 μm is
The nature of normal grain growth in the presence of a second phase deserves special consideration. The moving boundaries will be attached to the particles exert a pulling force on the boundary restricting its motion. Therefore if the boundary intersects the particle surface at 90° the particle will feel a pull of (2πrγcosΘ)*sinΘ. This will be counterbalanced by an equal and opposite force acting on the boundary. As the boundary moves over the particle surface Θ changes and the drag reaches a maximum value, this happens when Θ becomes______
Grain boundary diffusion makes a significant contribution to the total flux when___(Db and D1 are the diffusivities through the grain boundary and defect free lattice and ȣ, d are the effective thickneβ and grain size).
The grain boundary is made of a regular array of edge dislocation at define spacing. In the case of low angle grain boundary, the distance between dislocation array will be small, and for high angle grain boundaries, it will be large.
Kamala has three cylindrical containers, each with radius 20 cm that she wants to fill with grain. If her bag of grain contains 100 kg of grain, and she fills all three containers to a height of 70 cm, how much grain will be left in the bag, if 1 kg grain occupies 3000 cm3 space? (Use π = \(\frac{{22}}{7}\))
Which of the following is NOT true about Frictional force? A. Friction is the force which opposes the relative motion of two surfaces in contact. B. The force of friction that acts when a body is moving (sliding) on a surface is called sliding friction. C. Friction in machines wastes energy and also causes wear and tear. D. Rolling friction is much more than sliding friction, the use of ball bearings in a machine considerably reduces friction.
The boundary layer thickness at a distance of l m from the leading edge of a flat plate, kept at zero angle of incidence to the flow direction, is O.l cm. The velocity outside the boundary layer is 25 ml sec. The boundary layer thickness at a distance of 4 m is (Assume that boundary layer is entirely laminar)
Find the frequency factor of the following grain boundary diffusion, if the activation energy is given as 90KJ/mol and the diffusivity at the grain boundary at 1071K is given as 49*10-6m2/sec?