Question

Assertion: In high altitudes one sees colourful curtains of light hanging down from high altitudes.
Reason: The higher energy charged particles from the sun are deflected to the polar region by the magnetic field of the earth.
A) Both assertion and reason are correct and reason is the correct explanation for assertion.
B) Both assertion and reason are correct but reason is not the correct explanation for assertion.
C) Assertion is correct but reason is incorrect.
D) Both assertion and reason are incorrect.

Answer 1

Hint- In high-altitude regions like the arctic and Antarctic regions, there is a beautiful event of light occurring. This event is called ‘Aurora borealis’ in the northern region and ‘Aurora australis’ in the southern region. These are also called northern and southern lights.

Complete step by step answer:

In high altitudes like the southern and northern side, auroras occur. These auroras are caused by the collision between the particles from space and the particles in our atmosphere.

The particles from space are fast-moving electrons which originated in the magnetosphere. This magnetosphere is the space due to the Earth’s magnetic field.

These electrons from the magnetosphere impart its energy to oxygen and nitrogen molecules and make it to excite from its ground state. After some time, it returns to its ground state.

While returning to the ground state, the molecules emit photons. These photons are viewed as a colourful light to our eyes.

 In the reason, it states that the higher energy charged particles called the fast-moving electrons are collided/deflected by the particle in the polar region causing the curtain of light to occur.

Hence the reason matches the assertion. Therefore, the correct option is A.

Additional information: Many colours occurred in the aurora this is due to the energy exchanged by the electrons given to the molecules to excite the molecules. The wavelength of the photon released by the molecules coming from the excited state to the ground state determines the colour of the aurora.

Note: The auroras are occurring on both sides of the polar region. The auroras are of different shapes. The shape of the aurora depends on the magnetosphere from where the electrons are coming from. Auroras are occurring in the ring-shaped areas around the magnetic poles of the earth.