Which one of the following phenomena cannot be attributed to the refraction of light?

• Twinkling of stars

• Mirage

• Rainbow

• Redshift

During day time, plants absorb

• O₂

• CO₂

• N₂

• CO

Eyes of potato are useful for

• nutrition

• respiration

• reproduction

• vegetative propagation

Nitrous oxide is called

• laughing gas

• tear gas

• producer gas

• methane gas

Which of the following animals has the longest life span?

• Elephant

• Crocodile

• Dog

• Tortoise

Vapour pressure of liquid depends upon the

• quantity of heat

• temperature of liquid

• specific heat of liquid

• density of liquid

Force can be defined on the basis of

• Newton's second law of motion

• Newton's first law of motion

• Newton's third law of motion

• Newton's law of gravitation

Slope of the velocity-time graph gives the

• distance covered by a moving body

• velocity of a moving body

• acceleration of a moving body

• None of the above

The radioactive isotope of hydrogen is called

• deuterium

• protium

• radium

• tritium

Emission of which one of the following will produce isobars?

• Alpha particles

• Beta particles

• Gamma rays

• X-rays