Answer: b

Explanation:

Magneto-hydrodynamics (MHD) is the principle of energy production based on the direct conversion of thermal energy into electrical energy. Right now this theory is still in the experimental stage. Intensive research on this technology is going on in Russia, United States of America, Japan, China, Netherlands, Australia, Poland and Finland. Hence statement I is correct.

Through this technology, very high temperature (2800 Kelvin) is required to directly convert thermal energy into electrical energy by the flow of conducting fluid on the magnetic surface.

In magneto hydrodynamics system, the generator is installed in a single unit without moving parts. Coal based Magneto Hydrodynamics Research Project in India is being conducted at a 5 MW thermal power scale installed plant at Tiruchirappalli, Tamil Nadu. Hence, statement II is correct.

Here, statements I and II both are correct but statement-II is not the correct explanation of statement-I. Hence, option (b) is correct.

Answer: d

Explanation:

In order to implement nuclear power generation, Nuclear Power Corporation of India Limited was established in 1987 in place of Nuclear Power Board. This corporation is responsible for the design, construction work and production of all the nuclear power plants in the country.

Tarapur Atomic Power Station, established with the assistance of the United States, is India's first nuclear power plant. Under this plant, two units of boiling water reactor with capacity of 160 MW are working. The fuel required for this power plant will be supplied by the United States till the end. Tarapur Nuclear Power Plant supplies electricity to two western states of India - Maharashtra and Gujarat. Hence, statement 1 is correct.

Rawatbhata Atomic Power Station, located in Rajasthan, was established in 1970 and is the second nuclear power plant in India. Initially, the project was started with Canadian collaboration but later it was completed with indigenous technology. Hence, statement 2 is correct.

Answer: d

Explanation:

A propulsion system is a machine that produces thrust to push an object forward. The word propulsion comes from two Latin words: pro, meaning before or forward and pelere, meaning to propel. Propulsion means the action of moving an object forward. There are mainly four types of propulsion systems – Propeller, Turbine (or Jet) Engine, Ramjet and Rocket. The missile is propelled by a rocket or jet engine. Hence, option (d) is correct.

Answer: c

Explanation:

A missile is a pilotless, self-propelled and target-guided weapon system, which is used to carry the payload to a fixed point for the purpose of destroying an enemy position or target. The major technologies/mechanisms used in the missile are – propulsion system, guidance system and aerodynamic features including air frame, wings, fins. The function of the guidance system is to maintain the missile on the desired flight path. This system accomplishes this task by using Altitude Control Mechanism. The guidance system works like an auto-pilot. Hence, all statements are correct.

Answer: c

Explanation:

The world's first water-wave laser has been created by Israeli scientists. It emits laser light beam through the interaction of light and water waves. Researchers have created a device in which light from an optical fiber is shone on a small drop of water. Hence, statement 1 is correct.

Inside the drop, light waves and water waves pass through each other and emit energy in the form of a water-wave laser. It can be used in 'Lab-on-a-chip' devices to study cell science, test new drug treatments, etc. Also, it can be used in tiny/micro sensors. Hence, statement 2 is correct.