A magnetic field is produced by a magnetic material such as Iron, Cobalt or Nickel. Magnetic field are magnetic lines of force i.e. the region which experiences magnetic force. Earth acts as a huge bar magnet and has magnetic field around it due to which we are shielded by solar particles and experience phenomenon such as Auroras.
The earth acts as bar magnet due to presence of iron and nickel in molten form in its core. The outer core is liquid and moves generating a magnetic field. Thus, the correct options are:
All the statements can be used to explain about Earth's magnetic field.
Earth's magnetic field is almost same to that of the bar magnet. The magnetic field of the earth occurs from its core. It has an inner core which is solid in nature. in the outer core, there is a motion of the liquid due to heat flow from the inner core to the core mantle boundary which proves that the outer core is liquid and moving. The Earth's core consists of iron and nickel as the Eddy currents in the iron and nickel liquid helps generating the Earth's magnetic field.
Hence, all the three statements are true and can be used to explain the Earth's magnetic field.
The correct option is DISPERSION OF LIGHT AS IT ENTERS EARTH'S ATMOSPHERE. Scientists use astronomical spectrometer to analyse the composition of the sun and the stars. Astronomical spectrometer works on the basis of dispersion of light as it enters the earth's atmosphere.
