Explanation

(a) \(\frac{4\frac{2}{9} - 1\frac{13}{15}}{2\frac{1}{5} + \frac{4}{7} \times 2\frac{1}{3}}\)

\(4\frac{2}{9} - 1\frac{13}{15} = \frac{38}{9} - \frac{28}{15}\)

= \(\frac{190 - 84}{45}\)

= \(\frac{106}{45}\)

\(2\frac{1}{5} + \frac{4}{7} \times 2\frac{1}{3} = \frac{11}{5} + (\frac{4}{7} \times \frac{7}{3})\)

= \(\frac{11}{5} + \frac{4}{3}\)

= \(\frac{33 + 20}{15}\)

= \(\frac{53}{15}\)

\(\therefore \frac{4\frac{2}{9} - 1\frac{13}{15}}{2\frac{1}{5} + \frac{4}{7} \times 2\frac{1}{3}} = \frac{106}{45} \div \frac{53}{15}\)

= \(\frac{106}{45} \times \frac{15}{53}\)

= \(\frac{2}{3}\)

(b) \(\frac{7\sqrt{5}}{\sqrt{7}}\)

= \(\frac{7\sqrt{5}}{\sqrt{7}} \times \frac{\sqrt{7}}{\sqrt{7}}\)

= \(\frac{7\sqrt{35}}{7}\)

= \(\sqrt{35}\)

Correct Answer: D. arrogant

Correct Answer: A. the division of the Kingdom of Israel

Correct Answer: D. expelled

Explanation

The correct answer is D. expelled.

The phrase It is time we... is an idiom used to say that something should be done now, or that it is overdue. After It is time + subject, we typically use the simple past tense to refer to an action that should happen now or in the near future.

• It is time we expelled this irresponsible member. (Meaning: We should expel this member now.)

• It's time you went to bed. (Meaning: You should go to bed now.)

• It's time they fixed this problem. (Meaning: They should fix this problem now.)

Correct Answer: C. regulates the amount of light entering the eye

Correct Answer: D. ±2

Explanation

(a)(i) To prevent exploitation of consumers by middlemen and producers.

(ii) To avoid or control inflation.

(iii) To help low income earners e.g. minimum wage.

(iv) To control the profits of companies (especially monopoly).

(v) To prevent fluctuation of prices of some products e.g. agricultural produce.

(vi) To stabilize the income of some producers, e.g. farmers.

(vii) To make possible planning for future output.

(viii) To accumulate surplus for government.

(b)(i) It stimulates excess demand which cannot be satisfied i.e. shortages in the market.

(ii) It encourages hoarding of commodities by sellers so as to sell above the maximum price.

(iii) It leads to creation of parallel markets or under-the-counter sales. In this case the goods disappear from the open markets.

(iv) It encourages conditional sales. In this case, buyers are forced to purchase what they do not need in addition to what they need.

(v) Shortages result in queues. People have to line up so as to obtain some of the available goods.

(vi) It leads to rationing. Consumers are allocated a specific quantity irrespective of their need.

(vii) Preferential treatment is encouraged. Here, sellers prefer to sell to regular customers, friends and relatives.

Correct Answer: A) polarization

Explanation

In a simple cell, such as the Daniell cell, there are two electrodes made of different metals immersed in an electrolyte. One of the electrodes is made of copper. During the electrochemical reactions occurring in the cell, hydrogen gas bubbles may form around the copper electrode.

Polarization is the correct answer here because it refers to the buildup of excess charges or a decrease in the difference in potential between the two electrodes, which can hinder the flow of electrons and the overall functioning of the cell. In this case, the formation of hydrogen gas bubbles around the copper plate leads to polarization.

Here is a brief description of the other options:

Depolarization is the process of reversing or reducing polarization, usually by adding a substance that reacts with the hydrogen gas or other polarizing species to prevent their buildup.

Local action refers to unwanted side reactions that occur at the surface of an electrode, leading to corrosion and reduced efficiency of the cell. This is not related to the hydrogen gas bubbles forming around the copper plate.

Amalgamation is a process used in some electrochemical cells, where the surface of an electrode (usually zinc) is coated with a thin layer of mercury to reduce local action and polarization. This option is not directly related to the formation of hydrogen gas bubbles around the copper plate.

Therefore, the formation of hydrogen gas bubbles around the copper plate of a simple cell is due to polarization.

Correct Answer: C. net migration

Explanation

The net migration rate is the difference between the number of immigrants (people coming into an area) and the number of emigrants (people leaving an area) throughout the year.

Correct Answer: D. 0.20