1. Which is longest tributary river of India ?

Answer: Yamuna

2. Which is longest river of India

Answer: Ganges

3. Which is smallest state by area of India ?

Answer: Goa

4. Longest rail tunnel in the world ?

Answer: Seikan Tunnel (Japan - 53.9 Km)

5. Which is longest river in world ?

Answer: Nile, Africa

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 the brightest planet ?

Answer: Venus