POLARITY IN DC ARC WELDING

1. How many kinds of polarity in DC arc welding?

    (a) Three

     (b) Four

     (c) Two

     (d) Five

      Ans. (c)

 2. In DC welding heat distribution is possible between electrode and the base metal due to the change of polarity. The distribution  of heat is

      (a) Positive 2/3 and negative 1/3

      (b) Positive 1/3 and negative 2/3

      (c) Positive 3/4 and negative 1/4

      (d) Positive 1/4 and negative 3/4

     Ans. (a)

3. In DC welding, straight polarity is recommended for

      (a) welding with light coated electrodes

      (b) welding with heavy coated electrodes

      (c) welding with super heavy coated electrodes

      (d) sheet metal welding

       Ans. (a)

4. Which type of polarity is used in welding non ferrous metals?

      (a) AC transformer

      (b) Reverse polarity

      (c) Straight polarity

      (d) DC motor generator set

       Ans. (b)

5.  Which type of polarity is used in sheet metal welding?

      (a) AC transformer

      (b) Reverse polarity

      (c) straight polarity

      (d) Rectifier set

      Ans. (b)

6. Which type of polarity is used in welding with heavy and super heavy coated electrodes?

      (a) AC transformer

      (b) Reverse polarity

      (c) Straight polarity

      (d) DC motor generator set

       Ans. (b)

7. Which type of polarity is used in welding of cast iron?

      (a) AC transformer

      (b) Reverse polarity

      (c) Straight polarity

      (d) DC motor generator set

  

       Ans. (b)

8. Which type of polarity is used in welding in horizontal, vertical and overhead positions?

      (a) AC transformer

      (b) Reverse polarity

      (c) Straight polarity

      (d) DC motor generator set

        Ans(b)

9. The indication of wrong polarity in D.C. welding will result in

      (a) the electrode will become red hot 

      (b) excess spatter and poor penetration 

      (c) the electrode will freeze with the job

      (d) it will produce edge plates melted off

        Ans. (b)

10. Which types of polarity used in aluminium welding?

      (a) AC transformer

      (b) Reverse polarity

      (c) straight polarity

      (d) Rectifier set

        Ans. (b)

11. What is polarity?

        (a) Circuit of current

        (b) Direction of current

        (c) Open circuit of current

        (d) Opp direction of current

        Ans. (b)