Science & Technology

Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when: 1. The orbit is geosynchronous. 2. The orbit is circular. 3. The orbit lies in the plane of the Earth’s equator. 4. The orbit is at an altitude of 22,236 km. Select the correct answer using the codes given below:

At present, scientists can determine the arrangement or relative positions of genes or DNA sequences on a chromosome. How does this knowledge benefit us? 1. It is possible to know the pedigree of livestock. 2. It is possible to understand the causes of all human diseases. 3. It is possible to develop disease-resistant animal breeds. Which of the statements given above is/are correct?

Microbial fuel cells are considered a source of sustainable energy. Why? 1. They use living organisms as catalysts to generate electricity from certain substrates. 2. They use a variety of inorganic materials as substrates. 3. They can be installed in waste water treatment plants to cleanse water and produce electricity. Which of the statements given above is/are correct?

When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies because

A layer in the Earth’s atmosphere called Ionosphere facilitates radio communication. Why? 1. The presence of ozone causes the reflection of radio waves to Earth. 2. Radio waves have a very long wavelength. Which of the statements given above is/are correct?

The function of heavy water in a nuclear reactor is to

A company marketing food products advertises that its items do not contain trans-fats. What does this campaign signify to the customers? 1. The food products are not made out of hydrogenated oils. 2. The food products are not made out of animal fats/oils. 3. The oils used are not likely to damage the cardiovascular health of the consumers. Which of the statements given above is/are correct?

The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason ?

What is the difference between Bluetooth and Wi-Fi devices ?

Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use?

What is the difference between a CFL and an LED lamp? 1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi-conductor material. 2. The average life span of a CFL is much longer than that of an LED lamp. 3. A CFL is less energy-efficient as compared to an LED lamp. Which of the statements given above is/are correct?

A married couple adopted a male child. A few years later twin boys were born to them. The blood group of the couple is AB positive and O negative. The blood group of the three sons is A positive, B positive, and O positive. The blood group of the adopted son is

A new optical disc format known as the Blu-ray Disc (BD) is becoming popular. In what way is it different from the traditional DVD? 1. DVD supports Standard Definition video while BD supports High Definition video. 2. Compared to a DVD, the BD format has several times more storage capacity. 3. Thickness of BD is 2.4 mm while that of DVD is 1.2 mm. Which of the statements given above is/are correct?

An artificial satellite orbiting around the Earth does not fall down. This is so because the attraction of Earth

What is the difference between asteroids and comets? 1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material. 2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury. 3. Comets show a perceptible glowing tail, while asteroids do not. Which of the statements given above is/are correct?

Regular intake of fresh fruits and vegetables is recommended in the diet since they are a good source of antioxidants. How do antioxidants help a person maintain health and promote longevity?

What is "Virtual Private Network"?