Question 1
- State three characteristics of sial.
- Outline two characteristics of the troposphere.
Answer
-
- Sial is made up of light rocks/2.7g/cc / floats on sima.
- Sial is made up of granitic/ sedimentary/ metamorphic rock
- Contains 75% of the total gaseous mass of the atmosphere
- 90% of water vapour found in this layer. -
- Most weather phenomena occur in this layer
- Contains the weather making constituent/life supporting layer
- Temperature decreases with increase in altitude (positive lapse rate)/ rate of 6.50C per 1000m.
Question 2
- What is a longitude?
- What is the longitude of station X when it is 8.00 a.m. where in Nairobi at longitude 370E is 12.00 noon?
Answer
-
- This is the angular distance showing how far a place is west or east of the prime meridian
or
- An imaginary line on the map/globe running from North pole to south pole showing how far a place is west or east of the prime meridian.
Question 3
- State three causes of earth movements.
- Name two main earthquake zones in the world.
Answer
-
- Istatic adjustment.
- Gravitative pressure
- Magma movement within the crust.
- Convectional currents in the mantle -
- The curcum pacific belt
- The mid atlantic ridge
- Rift valley
Question 4
- Name two features found on emerged high land coast.
- State three conditions necessary for the formation of a spit.
Answer
-
- Raised cliffs
- stumps
- raised wave cut platform -
- The waves must carry large amount of load/ ample supply of sand being transported.
- The long shore drift must be weak
- It must be a shallow shore/continental shelf
- Waves must have a strong swash and weak backwash/constructive waves.
Question 5
- The diagram below shows a barchan
- Name the feature marked P.
- Name the wind marked Q.
- How is a deflation hollow formed
Answer
-
- P - Gentle slope
- Q - Eddy current
-
- Pre-existing depressions/localized fault is deepened by eddy action
- Gradually the depression is excavated through removal of the unconsolidated materials by wind abrasion/by deflation
- The depression is deepened then eddy currents develop causing more erosion
- The depression is a deflation hollow.