Helium is preferred to hydrogen in air balloons because it:

• is cheaper
• is less dense
• has greater lifting power
• does not form an explosive mixture with air
Correct Option: D  [ does not form an explosive mixture with air ]

Remark:

Ramsar Convention is for the conservation of:

• Mountain
• Grassland
• Forest
• Wetland
Correct Option: D  [ Wetland ]

Remark:

Which of the following is a non metal that remains liquid at room temperature?

• Phosphorous
• Bromine
• Chlorine
• Helium
Correct Option: B  [ Bromine ]

Remark:

A CD-ROM is a kind of:

• Optical disk
• Magnetic disk
• Fibre disk
• None of these
Correct Option: A  [ Optical disk ]

Remark:

"Curie" is unit of:

• Radioactivity
• Temperature
• Heat
• Energy
Correct Option: A  [ Radioactivity ]

Remark: Curie (Ci): One of three units used to measure the intensity of radioactivity.
The original unit for measuring the amount of radioactivity was the curie (Ci)–first defined to correspond to one gram of radium-226.

Normal human blood is:

• Acidic
• Alkaline
• Neutral
• Variable
Correct Option: B  [ Alkaline ]

Remark:

Arya Bhatt was a renowned Indian

• Chemist
• Physician
• Astronomer
• None of these
Correct Option: C  [ Astronomer ]

Remark: Aryabhata was a renowned ancient Indian mathematician and astronomer. He lived during the period of Gupta Empire.

Which of the following gases constitutes the major portion of the atmosphere by volume ?

• Oxygen
• Argon
• Nitrogen
• Carbon dioxide
Correct Option: C  [ Nitrogen ]

Remark:

What is Air Quality Index ?

• It tells about sound pollution.
• It measures air pollution mainly sulphur content in the air.
• It measures ozone levels in the selected area.
• It checks the colour of the air.
Correct Option: C  [ It measures ozone levels in the selected area. ]

Remark:

Acid rain is caused due to the pollution of environment by:

• Carbondioxide and Nitrogen
• Carbon monoxide and Carbondioxide
• Ozone and Methane
• Some oxide of Nitrogen and Sulpher
Correct Option: D  [ Some oxide of Nitrogen and Sulpher ]

Remark: Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air