1. Which is Longest Dam in India ?

Answer: Hirakod Dam (Orissa)

2. Which is the Densest populated State of India ?

Answer: West Bengal

3. Which Indian state is having longest coastline ?

Answer: Gujrat

4. Which is the largest sea in the world ?

Answer:

Philippine Sea

5. Which is the largest Zoo in India ?

Answer: Zoological Gardens, Alipur, Kolkata

6. 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.

7. Which is smallest planet ?

Answer: Mercury