(i) Robots can work in extreme environmental conditions like extreme hot or cold, space of underwater.
(ii) In dangerous situations like bomb detection and bomb deactivation.
(iii) Robots are significantly used in handling materials in chemical industries especially in nuclear plants which can lead to health hazards in humans.
(iv) Robots can be used in outer space exploring stars and planets and to analyse the elements in the rock and soils on Mars.

No. They cannot replace humans completely in work places. Because,
(i) The robots are well programmed to do a job and if a small thing goes wrong it end up in a big loss of the company.
(ii) Robots can perform defined tasks and cannot handle unexpected situation.
(iii) They lack empathy and hence create an emotionless work place.
(iv) Humans cannot be replaced in decision making.
(v) If a robot malfunctions, it takes time to identify the problem, rectify it and enprogramme if necessary the process requires significant time. 

(i) Exploring stars, planets, etc. are some of the application of Robots in outer space.
(ii) Investigation of the mineralogy of the rocks and soils on Mars and analysis of element found in rocks and soils are done by Mars rovers of NASA and Mars path finder launched by India.

(a) Top-down approach:
(i) Nanomaterials are synthesised by breaking down bulk solids into nano sizes.
(ii) Example: Ball milling, sol-gel and lithography.

(b) Bottom-up approach:
(i) Nano materials are synthesised by assembling in atoms/molecules together. Selectively atoms are added to create structure.
(ii) Example: Plasma etching and chemical vapour deposition.

(i) Gravitational waves are the disturbances in the curvature of space-time and it travels with speed of light.
(ii) Any accelerated charge emits electromagnetic wave.
(iii) Similarly any accelerated mass emits gravitational waves but these waves are very weak even for masses like earth.
(iv) The strongest source of gravitational waves are black holes. The discovery of gravitational waves made it possible to study the structure of black holes since it is the strongest source of gravitational waves.
(v) In fact, the recent discoveries of gravitational waves are emitted by two black holes when they merge to a single black hole.
(vi) In fact, Albert Einstein. theoretically proposed the existence of 'gravitational waves' in the year 1915. After 100 years, it is experimentally proved that his predictions are correct.

(i) Robotics is an integrated study of mechanical engineering, electronic engineering, computer engineering, and science.
(ii) Robot is a mechanical device designed with electronic circuitry and programmed to perform a specific task.
(iii) These automated machines are highly Significant in this robotic era where they can take up the role of humans in certain dangerous environments that are hazardous to people like defusing bombs, finding survivors in unstable ruins, and exploring mines and shipwrecks.

(i) Face recognition.
(ii) Providing response to player's actions in computer games.
(iii) Taking decisions based on previous actions.
(iv) To regulate the traffic by analyzing the density of traffic on roads.
(v) Translate words from one language to another.

There are two ways of preparing the nanomateials, top down and bottom up approaches

(i) Particle physics deals with the theory of fundamental particles of nature and it is one of the active research areas in physics.
(ii) Initially it was thought that atom is the fundamental entity of matter.
(iii) In 1930s and it was established that atoms are made up of electrons, protons and neutrons.

(i) Nano-robots in blood stream to perform small surgical procedures, to fight against bacteria, repairing individual cell in the body.
(ii) It can travel into the body and once after the job is performed it can find its way out. Chinese scientists have created the world's first autonomous DNA robots to combat cancer tumours.