JAMB Geography 2016 Past Questions & Answers

Soil texture is the classification of soil based on the size of its particles. The main textural classes are sand, which has large particles; clay, which has very fine particles; and loam, which is a balanced mixture of sand, silt, and clay. Therefore, 'Sand, Loamy, and Clay' is the correct textual classification of soils.

Common mistake: Students may mistakenly choose option B, as 'Prismatic' and 'Columnar' are terms used to describe soil structure (the arrangement of soil particles), which is often confused with soil texture (the size of the particles).

Coal is a type of sedimentary rock formed from the remains of ancient plants that were buried and subjected to intense heat and pressure over millions of years. This process, known as carbonization, removes other elements and concentrates the carbon from the original plant matter. As a result, the main chemical element that makes up coal is carbon.

Common mistake: Students might mistakenly choose Iron because they associate both coal and iron ore with mining and heavy industry, but iron is a metal element, while coal is a carbon-based fossil fuel.

Due to the Earth's rotation, a force known as the Coriolis effect deflects moving objects. In the Northern Hemisphere, this force deflects ocean currents to the right, causing them to circulate in a large clockwise pattern. In the Southern Hemisphere, the deflection is to the left, resulting in an anticlockwise circulation. Therefore, the statement that circulation is 'Clockwise in the northern hemisphere' is a correct fact.

Common mistake: Students often choose option B because they remember the circulation is opposite in the two hemispheres but confuse the correct direction for each one, wrongly thinking it's anticlockwise in the north.

Faulting is a process where the Earth's crust cracks and shifts, creating deep depressions called rift valleys. Lake Malawi is located in the East African Rift Valley, which was formed by this exact process of faulting. The lake was created when this long, deep valley filled with water, making it a classic example of a rift valley lake.

Common mistake: Students often mistakenly choose Lake Victoria because it is also in East Africa, but it was formed in a shallow basin between the two arms of the Rift Valley, not by faulting within the valley itself.

This question requires you to determine the height of a point on a topographical map using contour lines. To find the approximate height, you must first identify the values of the contour lines surrounding the point 'x'. The point 'x' is located on a slope or hill, likely between the 390-meter and 400-meter contour lines, or it is a peak just above the 390-meter line. Since the point is higher than the 390-meter line, 395 meters is the most reasonable approximation among the options, representing a point halfway to the next interval or near a peak.

Common mistake: Students often make the mistake of choosing the value of the nearest visible contour line, such as 390 meters, without correctly estimating the point's height as it lies between two lines or above the last line.

To find the gradient, you must first calculate the Vertical Interval (VI), which is the difference in height between points G and H, and the Horizontal Equivalent (HE), which is the ground distance between the two points. The formula for gradient is the Vertical Interval divided by the Horizontal Equivalent (VI/HE). After finding the VI from the contour lines and calculating the HE using the map's scale, the resulting ratio is approximately $1/36$, which is expressed as 01:36.

Common mistake: Students often make mistakes by incorrectly converting the map distance to the Horizontal Equivalent using the scale, or by wrongly dividing the Horizontal Equivalent by the Vertical Interval.

This question requires you to identify a landform by reading a topographical map. A dry valley is a valley that was formed by a river in the past but no longer has a stream flowing through it. On a map, it is shown by V-shaped contour lines pointing towards higher ground, but without the blue line that represents a river, which is what the footpath between Y and Z crosses.

Common mistake: Students often mistakenly choose 'Spur' because they confuse the direction of the V-shaped contours, which point towards higher ground for a valley but away from higher ground for a spur.

To find the length of a winding feature like a road on a map, you must use a piece of thread or the edge of a paper to trace its path accurately. Once you have traced the full length of the road, you straighten the thread or paper and place it against the linear scale provided on the map. This process will show that the total distance of the main road is approximately 14 kilometers.

Common mistake: Students often make the mistake of measuring the straight-line distance between the start and end points of the road, which gives a shorter, incorrect length instead of tracing the actual winding path.

To calculate the area of a map extract, you need to determine its length and width in kilometers using the map's scale or grid lines. On standard topographical maps, each grid square represents 1 square kilometer (1km x 1km). The correct method is to count all the full squares within the map's boundary and then estimate the area of the partial squares along the edges. For the map in question, adding the area of the full squares and the estimated partial squares results in a total area of approximately 62.0 sqkm.

Common mistake: A common mistake is to only count the full grid squares and ignore the partial ones, or to roughly estimate the length and width and multiply them (e.g., 8km x 8km = 64 sqkm) without a careful count.

Freetown is the correct answer because its port is located on the Sierra Leone River estuary, which forms one of the largest and deepest natural harbours in the world. This natural feature provides excellent shelter and deep water for large ships, making it an ideal site for a port without needing extensive man-made breakwaters. Other ports like Lagos and Tema required significant construction to become effective.

Common mistake: Students often mistakenly choose Lagos because it is a very busy and well-known port in Nigeria, confusing economic importance with having the best natural site.