Related Questions

If a gas metal arc process uses a low arc voltage and the arc is continuously interrupted as the molten electrode metal fills up the arc gap is known as
A ARC
B Short ARC
C ARC length
D ARC blow
In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as
A maximum grid voltage
B critical grid voltage
C any of the above
D none of the above
The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?
A They are mechanically strong
B They do not require any voltage for filament heating
C Both (A) and (B)
D None of the above
Mercury, in arc rectifiers, is chosen for cathode because
A Its ionization potential is relatively low
B Its atomic weight is quite high
C Its boiling point and specific heat are low
D All of the above
In a grid control of mercury arc rectifiers when the grid is made positive relative to cathode, then it the electrons on their may to anode.
A accelerates
B decelerates
C any of the above
D none of the above
In a three-phase mercury arc rectifiers each anode conducts for
A One-third of a cycle
B One-fourth of a cycle
C One-half a cycle
D Two-third of a cycle
Capillary rise of mercury in a small diameter tube is proportional of (where, d = mercury of the rube, σ = surface tension of mercury)
A d
B 1/d
C σ
D 1/σ
The potential drop in the arc, in a mercury arc rectifier, varies
A 0.05 V to 0.2 V per cm length of the arc
B 0.5 V to 1.5 V per cm length of the arc
C 2 V to 3.5 V per cm length of the arc
D none of the above
In a metal arc welding process, a gas metal arc welding with magnetized flux is used and can be done in all the positions i.e. flat position, vertical position or inclined position.
A Globular transfer
B Spray transfer
C GMAW practice
D Dip transfer
In DC arc welding, if leads are arranged in work as Negative pole of the welding arc and electrode as Positive pole of the welding arc, the arrangement is known as
A Fusion
B Reverse polarity
C Forward welding
D Direct polarity

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