288. Core prints are used to
A.Strengthen core
B.Form seat to support and hold the core in place
C.Fabricate core
D.All of the above

---

289. Jolt machines produce
A.Uniform ramming about the pattern
B.Uniform ramming about the flask
C.Uniform distribution throughout
D.Pack sand loosely all around

---

290. Blow holes are casting defects
A.Which occur due to some sand shearing from the cope surface
B.Which take the form of internal voids or surface depression due to excessive gaseous material not able to escape
C.Which occur due to discontinuity in metal casting resulting from hindered contraction
D.Caused by two streams of metals that are too cold to fuse properly

---

291. In salvage repair of castings, the most satisfactory and commonly used method of rectifying and repairing the defect
A.Brazing md soldering
B.Metal spraying
C.Painting
D.Galvanizing

---

292. Cold ducts are
A.Forging defects due to insufficient filling
B.Pores in welds
C.Casting defects due to two streams not able to fuse due to being cool
D.Casting defects due to moisture

---

293. Molten iron is desulphurized by adding following to the ladle
A.Carbon
B.Ferro-manganese
C.Ferro-silicon
D.Soda ash

---

294. Which is incorrect statement about results of cold working
A.It increases corrosion resistance
B.It increases strength, elasticity and hardness with a corresponding decrease in ductility
C.Handling of parts is easier
D.Dimension tolerances and finish are high

---