1. At sunrise and sunset, the sun is closer to the horizon. The sunlight near the horizon passes through denser layers of the air and covers larger distance before reaching our eyes. Most of the blue light gets scattered. The light that reaches our eyes is of longer wavelengths, mainly orange and red.Read more

    At sunrise and sunset, the sun is closer to the horizon. The sunlight near the horizon passes through denser layers of the air and covers larger distance before reaching our eyes. Most of the blue light gets scattered. The light that reaches our eyes is of longer wavelengths, mainly orange and red. That is why the sun appears red at the sunrise and at the sunset.

    See less
    • 0
  2. The sky appears blue when the scattering of light takes place through the atmosphere.The blue color of the sky is due to scattering of light from the atmosphere.As there is no atmosphere in space and hence light does not scatter into its constituent colors that is why the sky appears dark instead ofRead more

    The sky appears blue when the scattering of light takes place through the atmosphere.The blue color of the sky is due to scattering of light from the atmosphere.As there is no atmosphere in space and hence light does not scatter into its constituent colors that is why the sky appears dark instead of blue to an astronaut in space.

    See less
    • 1
  3. c) Nuclear energy Nuclear energy is produced by nuclear fusion and nuclear fission. In nuclear fission, uranium atoms are bombarded with low energy neutrons resulting in splitting of the atom into two relatively lighter nuclei. In nuclear fusion, lighter nuclei are fused together to form a relativelRead more

    c) Nuclear energy

    Nuclear energy is produced by nuclear fusion and nuclear fission. In nuclear fission, uranium atoms are bombarded with low energy neutrons resulting in splitting of the atom into two relatively lighter nuclei. In nuclear fusion, lighter nuclei are fused together to form a relatively heavier nuclei. The energy produced in nuclear reaction is tremendous and can be carried out in the absence of sunlight.

    Geothermal energy is obtained from the deep stored energy in the form of heat in the earth’s crust. The uneven heating of the earth’s surface results in wind movement and bio-mass is obtained from the dead remains of the plants and the animals.

    See less
    • 0
  4. c) Nuclear energy Bio-mass is obtained from the dead plants and animal wastes. In these dead plants and animals there is a chemical change as they react with water and sunlight. But nuclear energy is obtained by fusion and fission of atoms resulting in tremendous release of energy. Both nuclear fusiRead more

    c) Nuclear energy

    Bio-mass is obtained from the dead plants and animal wastes. In these dead plants and animals there is a chemical change as they react with water and sunlight. But nuclear energy is obtained by fusion and fission of atoms resulting in tremendous release of energy. Both nuclear fusion and fission can be carried out in the absence of the sunlight.

    Wood is a part of plant, gobar-gas is obtained from the animal dung and coal is obtained by the dead remains of the plants and animals. Therefore, they are all bio-mass energy products.

    See less
    • 0
  5. b) A cloudy day A solar water heater uses solar energy to heat water. On a cloudy day, the sunlight won’t be intense and bright enough and it gets reflected back in the sky from the clouds. This holds the sunlight from reaching the ground. Therefore, solar energy won’t be available for the solar watRead more

    b) A cloudy day

    A solar water heater uses solar energy to heat water. On a cloudy day, the sunlight won’t be intense and bright enough and it gets reflected back in the sky from the clouds. This holds the sunlight from reaching the ground. Therefore, solar energy won’t be available for the solar water heater to heat the water.

    See less
    • 0