Which gas shields the surface of the earth from ultraviolet radiation from the sun?
Ozone
Earth's UV Shield Gas Explained
The question asks to identify the specific gas responsible for protecting Earth's surface from the Sun's ultraviolet (UV) radiation.
Identifying the Ultraviolet Shield
The gas that shields the Earth's surface from harmful ultraviolet radiation originating from the Sun is Ozone.
- Ozone, with the chemical formula $O_3$, exists primarily in the stratosphere, forming the ozone layer.
- This layer acts as a natural filter, absorbing the majority of the Sun's dangerous UV-B and UV-C radiation.
- By absorbing this radiation, ozone prevents it from reaching the Earth's surface, thus protecting living organisms from its damaging effects, such as skin cancer and genetic mutations.
Why Other Gases Are Not the Primary UV Shield
Let's consider why the other options are incorrect:
- Nitrogen ($N_2$): The most abundant gas in the atmosphere, it does not effectively absorb UV radiation.
- Carbon dioxide ($CO_2$): This gas primarily absorbs infrared radiation (heat) and plays a role in the greenhouse effect, not UV shielding.
- Oxygen ($O_2$): While oxygen molecules absorb very high-energy UV radiation (UV-C) to form ozone in the upper atmosphere, molecular oxygen itself is not the primary shield against the UV radiation that reaches the lower atmosphere and surface.
Therefore, Ozone is the correct answer as it is the principal gas responsible for absorbing harmful UV radiation.
Important Questions from Miscellaneous
A stone is thrown horizontally from the top of a 20 m high building with a speed of 12 m/s. It hits the ground at a distance R from the building. Taking g = 10 m/s2 and neglecting air resistance will give :
A sphere of volume V is made of a material with lower density than water. While on Earth, it floats on water with its volume f1V (f1 < 1) submerged. On the other hand, on a spaceship accelerating with acceleration a < g (g is the acceleration due to gravity on Earth) in outer space, its submerged volume in water is f2V. Then:
A railway wagon (open at the top) of mass M1 is moving with speed v1 along a straight track. As a result of rain, after some time it gets partially filled with water so that the mass of the wagon becomes M2 and speed becomes v2. Taking the rain to be falling vertically and the water stationery inside the wagon, the relation between the two speeds v1 and v2 is :
Consider the following statements:
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
One block of 2⋅0 kg mass is placed on top of another block of 3⋅0 kg mass. The coefficient of static friction between the two blocks is 0⋅2. The bottom block is pulled with a horizontal force F such that both the blocks move together without slipping. Taking acceleration due to gravity as 10 m/s2, the maximum value of the frictional force is :
