Ques 21: ………..is essential in soil for plant growth.
- Carbon dioxide
- Oxygen
- Nitrogen
- Hydrogen
Ans- Nitrogen
Ques 22: Who discovered oxygen ?
- Albert Einstein
- john Emburey
- Graham Bell
- Joseph Priestly
Ans – Joseph Priestly
Ques 23: Urea fertilizer is ?
- Nitrogenous
- Potassium based
- Phosphoric
- Mixed
Ans – Nitogenous
Ques 24: Polio is caused by a type of
- Bacteria
- None of these
- Fungus
- Virus
Ans – Virus
Ques 25: What is Orion ?
- Constellation
- Meteor
- Galaxy
- Planet
Ans – Galaxy
Ques 26: How many colours are there in a spectrum of light ?
- 5
- 1
- 7
- 3
Ans – 7
Ques 27: Which types of pollution is responsible for Acid rains ?
- Soil pollution
- Air pollution
- Water pollution
- Noise pollution
Ans – Air pollution
Ques 28: In nuclear reactor heavy water is used as
- Moderator
- Atomic smasher
- Coolant
- Fuel
Ans – coolant
Ques 29: ………….. is produced by the vibration of bodies.
- Electricity
- Light
- Thunder
- Sound
Ans – sound
Ques 30: What is the chemical formula of Salt ?
- ZnC
- NaCl
- NaOH
- KCl
Ans – NaCI