question_answer

Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:

Electric conduction takes place in a discharge tube due to movement of (1) positive ions                (2) negative ions (3) electrons                      (4) photons

A)   1, 2 and 3 are correct

B)  1 and 2 are correct

C)   2 and 4 are correct

D)  1 and 3 are correct