GROWTH DEVELOPMENT CHILD
SUMMATIVE ASSESSMENT
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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P waves slow down and S waves stop
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S waves slow down and P waves stop
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Both P and S waves stop
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None of the above
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Detailed explanation-1: -While P-waves can travel through both solids and liquids, S-waves can only travel through solids. The P-waves will travel through the Earth’s outer core, but S-waves will not. Observing this difference tells us that the Earth must have a liquid outer core.
Detailed explanation-2: -P-waves bend slightly when they travel from one layer into another. Seismic waves move faster through denser or more rigid material. As P-waves encounter the liquid outer core, which is less rigid than the mantle, they slow down. This makes the P-waves arrive later and further away than would be expected.
Detailed explanation-3: -Scientists figured out that the outer core must be liquid because S waves do not pass through it, but P waves do. The behavior of P and S waves also indicates that the inner core is solid. The speed of seismic waves also depends on the density of the material through which they are traveling.
Detailed explanation-4: -P waves can travel through liquid and solids and gases, while S waves only travel through solids. Scientists use this information to help them determine the structure of Earth. For example, if an earthquake occurs on one side of Earth, seismometers around the globe can measure the resulting S and P waves. SF Fig.
Detailed explanation-5: -When P-waves strike the outer core, however, they bend downward when traveling through the outer core and bend again when they leave. This indicates that P-waves slow down in the outer core, suggesting that this layer has a significantly different composition from the mantle and may actually be liquid.