When pressure is increased, then the melting point of ice:

• Increases
• Decreases
• Remains unchanged
• Depends on the impurities in the ice
Correct Option: B  [ Decreases ]

Remark:

The optimum dissolved oxygen level (in mg/litre) required for survival of aquatic organism is:

• 4-6
• 2-4
• 8-10
• 12-16
Correct Option: A  [ 4-6 ]

Remark:

Cobalt-60, commonly used in radiation therapy, emits :

• Alpha rays
• Beta rays
• Gamma rays
• X-rays
Correct Option: C  [ Gamma rays ]

Remark:

In a forest ecosystem, green plants are

• the primary producers.
• the secondary consumers.
• the decomposers.
• both secondary consumers and decomposers.
Correct Option: A  [ the primary producers. ]

Remark: The green plant in the ecosystem are called producers. In a terrestrial ecosystem, major producers are herbaceous and woody plants. Likewise, producers in an aquatic ecosystem are various species like phytoplankton, algae and higher plants.

Who discovered Electron?

• Enrico Fermi
• Robert Noyce
• J.J.Thomson
• James Dyson
Correct Option: C  [ J.J.Thomson ]

Remark:

Which of the following will not cause any atmospheric pollution ?

• Hydrogen
• Sulphur dioxide
• Carbon dioxide
• Carbon monoxide
Correct Option: A  [ Hydrogen ]

Remark:

Sound waves having frequency less than 20 Hz are called __________ waves.

• Intelligent
• Inferior
• Infrasonic
• Instrumental
Correct Option: C  [ Infrasonic ]

Remark:

Which of the following is chiefly present in LPG?

• Methane
• Ethane
• Propane
• Butane
Correct Option: D  [ Butane ]

Remark:

Which of the following animals is carnivorous?

• Elephant
• Horse
• Rhinoceros
• Tiger
Correct Option: D  [ Tiger ]

Remark:

An instrument used for measuring depth of an ocean is called?

• Hydrometer
• Hygrometer
• Fathometer
• Galvanometer
Correct Option: A  [ Hydrometer ]

Remark: