1. In arc welding, eyes needed to be protected against
a. intense glare b. sparks c. infra-red rays d. infra-red and ultraviolet rays
2. In arc welding, the temperature of heat of arc is in the range
a. 1000 C to 2000 C b. 2000 C to 4000 C c. 4000 C to 6000 C d. 6000 C to 7000 C
3. Welding of steel structures on site of a building is done by
a. Spot welding b. Projection welding c. Seam welding d. Arc welding
4. In arc welding, current used is
a. A.C current of high frequency b. A.C current of low frequency
c. D.C current d. all of the above
5. in arc welding, with increase of thickness of material to be welded, the welding current requirement
a. increases b. decreases c. remains same d. none of the above
6. Welded rod coated with fluxing material is used in
a. gas welding b. shielded arc welding c. D.C arc welding d. argon arc welding
7. Main criterion for selection of electrode diameter in arc welding is
a. materials to be welded b. type of welding process c. thickness of material
d. voltage used
8. Material used for coating the electrode is called
a. protective layer b. binder c. slag d. flux
9. Open circuit voltage for an arc welding is of the order of
a. 18-40 volts b. 40-95 volts c. 100-125 volts d. 130-170 volts
10. When welding is going on, are voltage is of the order of
a. 18-40 volts b. 40-95 volts c. 100-125 volts d. 130-170 volts
11. In arc welding using direct current, amount of useful arc heat at the anode and cathode respectively are
a. one third and two third b. two third and one third c. equal d. none of the above
12. In arc welding using A.C amount of useful heat at the anode and cathode respectively are;
a. one third and two third b. two third and one third c. equal d. none of the above A
13. When the work is connected to the positive terminal and the electrode holder to the negative terminal, the welding set up is said to have
a. straight polarity b. reversed polarity c. both (a) or (b) above d. none of the above
14. When the work is connected to the negative terminal and the electrode holder to the positive terminal, the welding set up is said to have
a. straight polarity b. reversed polarity c. both(a) and (b) above d. none of the above
15. In arc welding, penetration is minimum for
a. DCRP b. DCSP c. A.C d. none of .the above
16. In arc welding, penetration is deeper for
a. DCRP b. DCSP c. A.C d. none of the above
17. Welding process, in which heat is produced for welding by chemical reaction, is known as
a. gas welding b. thermit welding c. forge welding d. resistance welding
18. In thermit welding, thermit used is mixture of
a. aluminium and iron oxide b. aluminium and charcoal c. iron oxide and charcoal
d. none of the above
19. In thermit welding, aluminium oxide are mixed in the proportion
a. 1:1 b. 1:3 c. 3:1 d. 2:1
20. Thermit welding is used for
a. joining rails, truck frames and broken motor castings
b. repairing broken shears
c. replacing broken gear teeth
d. all of the above
21. In gas welding, flame temperature of the oxyacetylene gas used is
a. 1200.C b. 1800.C c. 2400.C d. 3200.C
22. In gas welding, maximum flame temperature occurs at
a. inner cone b. outer cone c. next of inner cone d. tip of the flame
23. Acetylene gas is stored in cylinders in
a. solid form b. liquid form c. gaseous form d. all of the above
24. Chemical used in producing acetylene gas is
a. carbon b. crushed bone c. charcoal d. none of the above
25. Low pressure acetylene is produced at the welding site by chemical reaction between water and
a. calcium chloride b. calcium carbide c. calcium carbonate d. carbon