Which part of human eye has the maximum refractive index?

• Aqueous humour
• Vitreous humour
• Lens
• Cornea
Correct Option: D  [ Cornea ]

Remark: Refraction is the change in direction of light rays as they transition between different mediums. A figure of 1.376 is often quoted for the refractive index of the human cornea over the visible spectrum.

A heavy stone appears to be lighter in water. This is due to

• Upward pressure of water
• Downward pressure of water
• Lateral pressure of water
• None of these
Correct Option: A  [ Upward pressure of water ]

Remark: Water creates upward pressure due to the principle of buoyancy, as described by Archimedes' principle.

The isotope used for the production of atomic energy is:

• U-235
• U-238
• U-234
• U-236
Correct Option: A  [ U-235 ]

Remark:

Which metal is present in haemoglobin?

• Iron
• Zinc
• Magnesium
• Copper
Correct Option: A  [ Iron ]

Remark: Iron is an essential element for blood production, and about 70 percent of your body's iron is in the red blood cells called hemoglobin.

A CD-ROM is a kind of:

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

Remark:

Tetraethyl lead (TEL) is

• a catalyst used in burning fossil fuel
• an antioxidant
• a reductant
• an antiknock compound
Correct Option: D  [ an antiknock compound ]

Remark:

Which of the following is a greenhouse gas

• Chlorofluoro carbon
• Carbon
• Calcium
• None of these
Correct Option: A  [ Chlorofluoro carbon ]

Remark: Chlorofluorocarbons (CFCs) are considered greenhouse gases due to their ability to trap heat in the Earth's atmosphere.

Acid rain is caused by

• Humidity
• Pollutant gases
• Population explosion
• None of these
Correct Option: B  [ Pollutant gases ]

Remark:

A device that is responsible for changing the voltage is:

• Transformer
• Encoder
• Decoder
• Translator
Correct Option: A  [ Transformer ]

Remark:

Insecticides usually act upon:

• Muscular system
• Digestive system
• Nervous system
Correct Option: C  [ Nervous system ]

Remark: