Bissoy.com
Doctors Medicines MCQs Q&A

Gold has surface free energy of 1.5 J.m-2 and grain boundary energy of 0.365 J.m-2.The groove angle that forms where a grain boundary intersects the free surface in a well annealed sample is

Gold has surface free energy of 1.5 J.m-2 and grain boundary energy of 0.365 J.m-2.The groove angle that forms where a grain boundary intersects the free surface in a well annealed sample is Correct Answer 166°

Related Questions

Given that, 24 carat gold is pure gold, 18 carat gold is 3/4th of pure gold and 20 carat gold is 5/6th of pure gold, the ratio of the pure gold in 18 carat gold to the pure gold in 20 carat gold is -
Consider the following statements regarding V-belt drive : 1. The groove angle of the sleeve is less than the belt section angle 2. The efficiency of a V-belt drive is higher than that of a flat belt drive 3. The groove angle is so made that the belt gets wedged in the groove  Which of the above statements are correct ? 
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______
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.
Directions : In each of the following questions a statement is given, followed by two conclusions. Give answer :

Statements : The Bank of England's move to auction 25 metric tons of gold drew plenty of bidders looking for a bargain, but was criticised by major gold producers worldwide.

Conclusions :
I. The Bank of England should not auction gold which it possesses to keep steady international prices of gold.
II. Bidders should quote higher gold prices to retain present value of gold in the international markets.
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.
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).
John, Johny and Janardan participated in a race and each won a different medal among Gold, Silver and Bronze, not necessarily in that order. Each person among them gives two replies to any question, one of which is true and the other is false (in any order). When asked about the details of the medals obtained by them, the following were their replies: John: I won the Gold medal. Johny won the Bronze medal. Johny: John won the Silver medal. I won the Gold medal. Janardan: Johny won the Silver medal. I won the Gold medal. Which among the following is the correct order of the persons who won the Gold medal, the Silver medal and the Bronze medal respectively?
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 = \(\frac{{22}}{7}\))
S1: The role of the precious yellow metal is undergoing a dramatic change.
P: In developing countries like India, where gold is used mainly for ornaments, a distinct change in attitude is in the offing.
Q: Slowly, the use of gold in the form of ornaments will be on the decline and even if gold prices shoot up, women folk would not like to sell off their ornaments.
R: The yellow metal will soon be treated as an investment instrument.
S: The maxim, "Larger the gold reserves, richer the country" will not hold good for a long time.
S6: Again, it would not be an economic proposition to buy and sell gold ornaments as an instrument of investment as buying would be costlier and selling will be at a discount.

The Proper sequence should be: