01: Choose the correct answer (Answer 10 points only) (30 Marks) 1. Deformation in which stress and strain are proportional is called a) elastic deformation b) plastic deformation e) elasto-plastic deformation d) unrecoverable deformation 2- The ductility property can be studied at: a) micro structure scale b) macro structure scale c) nano structure scale d) micro and nano structure scale 3- Metals are sensitive to fatigue and less resistant to corrosion due to a) hardness b) ductility c) elasticity d) stiffness 4-The unique property of elastomers, the young modulus of elasticity a) decrease with temperature b) increase with temperature c) constant with temperature d) vary linearly with temperature 5- The ceramics strength in tension is.......... Than fatigue strength in compression a) much lesser b) much higher e) equal d) higher 6- Deformation in which stress and strain are not proportional is called a) plastic deformation b) visco clastic deformation c) elastic deformation d) elastic and plastic deformation 7- The metallic materials have good electrical conductivity due to a) atomic number b) valence electron c) number of electron in outer shell d) electronegativity 8- In engineering application when the strength per unit weight is important it is preferable to use a) Aluminum b) elastomers c) polymers d) glasses اجابتك 9- A metal which has very little plastic deformation is called a) ductile material b) tough material e) stiff material d) brittle material 10- The initial departure from lincarity of the stress strain curve called a) yield point b) proportional limit c) yield stress d) yield strength 11- In compression test the resulting stress strain curve in plastic region a) will be similar b) will be slightly similar c) will be slightly different d) will be different 12 - The value of hardness is 400 measured by knoop method, this value will corresponds: a) 350 Brinell hardness, 120 Brinell B and 33 Rockwell Cb) 350 Brinell hardness, 108 Brinell B and 40 Rockwell Cc) 350 Brinell hardness, 108 Brinell B and 33 Rockwell Cd) 300 Brinell hardness, 108 Brinell B and 33 Rockwell C