11. List two methods of producing magnetic fields.

1. By using a permanent magnet we can produce the magnetic field and it can be visualized by spreading iron fillings on a white paper and keeping a magnet beneath the paper.

2. A current-carrying straight conductor produces the magnetic field.

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).