Questions

Defence Research and Development Organisation (DRDO) has developed an unmanned, remotely operated tank which has three variants - surveillance, mine detection and reconnaissance in areas with nuclear and bio threats. It is called Muntra. 

Gear finishing operation is called Burnishing.

W is the symbol for chemical element Tungsten or Wolfram.

It is used in making filaments of bulbs.

France national football team has won the FIFA 2018 - an international football tournament contested by the men's national teams of the member associations of FIFA once every four years. It took place in Russia from 14 June to 15 July 2018.

When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at bottom also increases. Therefore the spring balance reading increases. Thus (a) is correct.