Grade 9 Earth Science-2

What is a volcano?

• The movement of the plate boundaries on the earth's crust.

• A mountain created by the faulting and folding of the earth's crust.

• An opening in the earth's crust through which lava, ash, and gases escape onto the surface.

• A landform which has a summit but no crater.

A type of volcano that is almost flat and broad like a warrior's shield.

• composite volcano

• lava dome

• cinder cone

• shield volcano

Which type of volcano has a broad base and steep side, usually has a large crater at the top and formed by alternating layers of magma and ash.

• cinder cone

• shield volcano

• composite volcano

• caldera

Mt. Mayon is an example of a _____ volcano because it is composed of alternating layers of pyroclastic fragments and solidified lava flows.

• cinder cone

• composite

• shield

• caldera

Identify the factor that affects the viscosity of the magma as shown in the figure.

• high silica content

• low gas content

• low temperature of magma

• high temperature of magma

Answer explanation

The viscosity of magma decreases with temperature. The higher the temperature of magma is, the lower is its viscosity. As lava flows, it cools and begins to harden, its ability to flow decreases and eventually it stops.

What do you call molten hot liquid rock while it is still below the Earth's surface?

• lava

• magma

• igneous

• mauna

What are the factors that affect volcanoes' eruptive style?

• magma's temperature

• chemical composition

• amount of dissolved gases

• all of the above

How can volcanoes affect the lives of people in a positive way or in a way that is beneficial to us?

• Many businesses will operate during volcanic eruption.

• Ash ejected by the volcano is good for the health.

• Habitats and landscapes are damaged by lava flows.

• Heat energy from volcanoes is used to generate electricity known as geothermal energy.

This type of geothermal power plant is more common and requires lesser temperature than a dry steam geothermal power plant.

• 
• 
• 
• none of the above

Which of the following is the CORRECT statement about geothermal energy?

• Geothermal energy is the heat energy present on the surface of the Earth.

• Geothermal energy is the heat energy present in the interior of the Earth.

• Geothermal energy is the heat energy present on the surface of the ocean.

• Geothermal energy is the heat energy present in the outer space.