Questions

B is correct, an abstract class need not implement any or all of an interface’s methods

Hydrogen Bomb is based on the principle of Nuclear Fusion.

• Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles.

• The difference in mass between the reactants and products is manifested as either the release or absorption of energy.

In 1861, civil war broke out in the USA. USA was the largest supplier of cotton to Britain. Once the civil war broke out, the demand for cotton from India became high and this led to a surge in cotton cultivation in India and there was a period of ‘boom’ then.In May and June 1875, peasants of Maharashtra in some parts of Pune, Satara and Ahmednagar districts revolted against increasing agrarian distress. The Deccan Riots of 1875 targeted conditions of debt peonage (kamiuti) to moneylenders.In 1879, the Agriculturists Relief Act was passed which ensured that the farmers could not be arrested and imprisoned if they were unable to pay their debts.

If some action has started in the past and is still continuing, then present perfect continuous tense should be used instead of present continuous tense. So, the phrase ‘am waiting’ needs to be replaced with ‘have been waiting’ to make the sentence contextually correct. Thus, the correct formation would be, ‘I have been waiting for three –quarters of an hour’.