Question Discussion & Solution

The cube is coloured on two adjacent faces (let us consider that the top and back surfaces are coloured)

So, the cubes on the surface having no colour will be 12 cubes on the front surface, 6 cubes on the right surface, 6 cubes on the left surface and 4 cubes at the bottom two surface.

So, cubes with no colour are:

12 + 6 + 6 + 4 = 28

Again, small cubes inside the big cube with no surface coloured is 8.

Therefore, cubes with no colour are = 28 + 8 = 36

The correct answer is option 4, i.e. Ocean, snow and rain, underground water.

• Water resources available on earth are :
  • Freshwater: Glaciers, ice caps, and snow
  • Groundwater
  • Oceans, seas, streams, rivers, lakes, ponds
  • Wetlands- lagoons, swamps, and marshes
  • Precipitation- Rain, snow, and dew

Hence, from the above points, we can clearly infer that the resources of water on the earth are ocean, snow and rain, underground water.

CONCEPT:

Rutherford’s Model of the Atom:

• He bombarded the beam of alpha particles on a very thin gold foil.
• While bombarding he observes the number of scattering of particles –
  • Most of the particles passed either un-deviated or with a very small deviation.
  • Some deviated by large angles
  • 1 out of 8000 was deflected by more than 90°
• The conclusion to this deflection:
  • Most of the space of an atom is empty.
  • At the centre of an atom having a tiny positively charged particle called a nucleus.
  • The centre nucleus has all the mass of an atom.
  • The amount of positive charge at the nucleus is equal to the total amount of negative charges on all the electrons of the atom.
  • All the electrons revolve around the nucleus and coulomb force provide the centripetal force

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EXPLANATION:

• After the α -particles scattering experiment, the following conclusions were made by Rutherford as regard as atomic structure:

• Most of the mass (at least 99.95%) and all of the charge of an atom concentrated in a very small region is called the atomic nucleus. Therefore option 4 is correct.
• The nucleus consists of proton and neutron, in which proton was first discovered by Rutherford but neutrons were later discovered by James Chadwick in 1932.
• In an atom, there is maximum empty space and the electrons revolve around the nucleus in the same way as the planets revolve around the sun and the nnumber of protons and electrons inside an atom are equal under normal conditions (non-ionized). 

16 = 4²

100 = 10²

196 = 14²

216 = 6³

16, 100 and 196 are the perfect squares whereas 216 is a perfect cube.

The correct answer is All of the above.

• Foreign Marriage Act,1969:
  • Section 4 of the act deals with the conditions relating to the solemnization of foreign marriages.

Key Points

• The act says that it solemnizes the marriage between parties one of whom which should be an Indian citizen under article 8 of the Indian Constitution or if the following conditions got satisfied:-
  • Spouse of both parties should not be living.
  • Both parties should be of sound mind.
  • At the time of marriage, the bridegroom should be of 21 years and the bride should be of 18 years.
  • Neither of the party is within the degree of prohibited relationship.
• With an element that personal law and custom laws governing at least one party permit marriage between them including that they are not within the degree of prohibited relationship.
• Section 5 of the act deals with the need for intended marriage.
• The section states that when a marriage is solemnized under this act the parties who got married have to give notice to the marriage officer of the district in writing specified in the First Schedule of the act.