Nuclear energy is the best alternative of fossil fuel because of its environment friendly nature.

What are fossil fuels ? State its disadvantages.

Statement A: We need to look for more and more source of energy. Reason R:There are only limited reserves of fossil fuels. Which option is correct for statement A and reason R?

To find out the names of organisations involved in spreading awareness about the conservation of natural resources. NGO (Non Government Organisations) such us SEACOLOGY and Mera Desh Foundation spread awareness about the environment and promote activities that lead to conservation of natural resources. Some other organisations that work for the conservation of the environment. CSE - The Centre for Science and Environment, TER- The Energy and Resources Institute, WTI - Wildlife Trust of India. How you can contribute towards the conservation of our environment and natural resources.

To find out the names of organisations involved in spreading awareness about the conservation of natural resources. NGO (Non Government Organisations) such us SEACOLOGY and Mera Desh Foundation spread awareness about the environment and promote activities that lead to conservation of natural resources. Some other organisations that work for the conservation of the environment. CSE - The Centre for Science and Environment, TER- The Energy and Resources Institute, WTI - Wildlife Trust of India. Which organisation(s) is/are active to spread awareness about conservation of our environment and natural resources in your village /town/city?

Two stars bound together by gravity orbit othe because of their mutual attraction. Such a pair of stars is referred to as a binary star system. One type of binary system is that of a black hole and a companion star. The black hole is a star that has cullapsed on itself and is so missive that not even light rays can escape its gravitational pull therefore when describing the relative motion of a black hole and companion star, the motion of the black hole can be assumed negligible compared to that of the companion. The orbit of the companion star is either elliptical with the black hole at one of the foci or circular with the black hole at the centre. The gravitational potential energy is given by U=-GmM//r where G is the universal gravitational constant, m is the mass of the companion star, M is the mass of the black hole, and r is the distance between the centre of the companion star and the centre of the black hole. Since the gravitational force is conservative. The companion star and the centre of the black hole, since the gravitational force is conservative the companion star's total mechanical energy is a constant. Because of the periodic nature of of orbit there is a simple relation between the average kinetic energy ltKgt of the companion star Two special points along the orbit are single out by astronomers. Parigee isthe point at which the companion star is closest to the black hole, and apogee is the point at which is the farthest from the black hole. Q. Which of the following prevents the companion star from leaving its orbit and falling the black hole?

Two stars bound together by gravity orbit othe because of their mutual attraction. Such a pair of stars is referred to as a binary star system. One type of binary system is that of a black hole and a companion star. The black hole is a star that has cullapsed on itself and is so missive that not even light rays can escape its gravitational pull therefore when describing the relative motion of a black hole and companion star, the motion of the black hole can be assumed negligible compared to that of the companion. The orbit of the companion star is either elliptical with the black hole at one of the foci or circular with the black hole at the centre. The gravitational potential energy is given by U=-GmM//r where G is the universal gravitational constant, m is the mass of the companion star, M is the mass of the black hole, and r is the distance between the centre of the companion star and the centre of the black hole. Since the gravitational force is conservative. The companion star and the centre of the black hole, since the gravitational force is conservative the companion star's total mechanical energy is a constant. Because of the periodic nature of of orbit there is a simple relation between the average kinetic energy ltKgt of the companion star Two special points along the orbit are single out by astronomers. Parigee isthe point at which the companion star is closest to the black hole, and apogee is the point at which is the farthest from the black hole. Q. For circular orbits the potential energy of the companion star is constant throughout the orbit. if the radius of the orbit doubles, what is the new value of the velocity of the companion star?

Compare and contrast fossil fuels and the sun as direct source of energy.

Choose the correct alternative : (a) If the zero of potential energy is at infinityn the total energy of an orbiting satellite is negative of its kinetic/potential energy. (b) The energy required to launch an orbiting satellite out of earth's gravitational influence is more/less than the energy required to project a stationary object at the same height (as the satellite) out of earth's influence.