Which of the following does not pollute the air?

A. Nitrogen dioxide
B. Sulfur dioxide
C. Carbon dioxide
D. None of these

kilohertz (kHz) is a unit which measures?

A. Power used by a current of one ampere
B. Electromagnetic radio wave frequencies
C. Voltage
D. Electric resistance

The study of heavenly bodies is known as_________?

A. Astrology
B. Astronautics
C. Astronomy
D. Astrophysics

Jupiter has ________ known moons.

A. 62
B. 73
C. 79
D.53

Second layer of Earth’s atmosphere is__________?

A. Stratosphere
B. Mesosphere
C. Troposphere
D. Thermosphere

In 2013, Planck measured the age of the universe at ___________?

A. 13.82 billion years
B. 4.53 billion years
C. 4.6 billion years
D. 4.53 billion years

Human beings use _______ liters of pure oxygen per day.

A. 550
B. 2500
C. 1,050
D. 10,000

The yellow colour in photochemical smog is due to the presence of____________?

A. Sulphur dioxide
B. Carbon dioxide
C. Nitrogen dioxide
D. Cfc’s

Why normal rain is slightly acidic?

A. Due to presence of dust in air
B. Carbon dioxide and water in clouds react to form carbonic acid
C. Ozone depletion
D. All of these

Disolved oxygen (DO) in water should be?

A. 400 to 800 ppm
B. 4000 to 8000 ppm
C. 0.4 to 0.5 ppm
D. 4 to 5 ppm