SSC CGL General Knowledge questions Set-1 (10 questions)

1. A concave lens always forms an image which is 

a real and erect 
b virtual and erect 
c real and inverted
d virtual and inverted

2. A vitamin requires cobalt for its activity. The Vitamin is 

a B12
b D
c B2 
d A

3. One of the constituents of tear gas is 

a Ethane
b Ethanol 
c Ether
d Chloropicrin