WAEC Past Questions and Answers - Page 3241

16,201.

A charge of 2.0 x 10\(^{-5}\) C experiences a force of 80N in a uniform electric field. Calculate the magnitude of the electric field intensity

A.

8.0 x 106 NC-1

B.

4.0 x 106 NC-1

C.

4.0 x 104 NC-1

D.

2.0 x 104 NC-1

Correct answer is B

E = \(\frac{F}{Q} = \frac{80}{2 \times 10^{-5}}\)

= 4 x 10\(^6\) NC\(^{-1}\)

16,202.

When a person holds a negatively charges metal rod and stands bare-footed on the ground, how will the charges leak?

A.

negative charges flows to the ground through the person's body

B.

positive charges flow from the ground through his body to neutralize the negative charges

C.

positive charges in the air neutralizes the negative charges the person is holding

D.

negative charges will leak through the air

Correct answer is A

No explanation has been provided for this answer.

16,203.

The eye defect caused by an uneven curvature of the cornea or lens or both is

A.

myopia

B.

presbyopia

C.

astigmatism

D.

hypermetropia

Correct answer is C

Astigmatism is a common refractive error of the eye that occurs when the cornea or lens has an irregular shape. In a normal eye, the cornea and lens have a smooth, evenly curved surface, similar to a sphere. However, in astigmatism, the cornea or lens may be more curved in one direction than the other, resulting in a refractive error.

16,204.

Stunted growth and small yellow leaves in plants are symptoms of the deficiencies of

A.

nitrogen

B.

iron

C.

sulphur

D.

magnesium

Correct answer is B

Iron deficiency in plants leads to chlorosis, which is the yellowing of leaves. Chlorosis occurs because iron is necessary for the formation of chlorophyll, which is the green pigment in plants that absorbs light energy for use in photosynthesis. Without sufficient iron, the plant cannot produce enough chlorophyll, leading to yellow leaves. Stunted growth is also a symptom of iron deficiency as iron is essential for various metabolic processes including DNA synthesis.

16,205.

An example of a process that involves osmosis is the

A.

movement of water from root hairs into cortical cell

B.

reabsorption of food nutrients from the kidney into blood capillaries

C.

translocation of starch from leaves to all parts of a plant

D.

movement of digested food from ileum into blood capillaries

Correct answer is A

Movement of water from root hairs into cortical cells involves osmosis. When a plant's roots absorb water from the soil, it passes through the root hairs and moves into the cortical cells (which are part of the root's inner layer) through osmosis. This osmotic movement of water helps maintain water balance and nutrient distribution within the plant.