1. Which is the lightest metal ?

Answer: Lithium

2. Where is largest Archipelago ?

Answer: Indonesia

3. Which is Highest Battle field ?

Answer: Siachin Glacier. Mastguru team Salutes to Indian soldiers.

4. Which is highest dam in world ?

Answer:

Jinping-I Dam - 305 m (1,001 ft) in China on Yalong river.
Second Highest is Nurek Dam 300 m (980 ft) Tajikistan on Vakhsh river.

5. Longest rail tunnel in the world ?

Answer: Seikan Tunnel (Japan - 53.9 Km)

6. Which is Longest road tunnel in the World ?

Answer: Lærdal Tunnel (Norway - 24.51 kilometre)

7. Which is the lightest gas ?

Answer: Hydrogen