Questions

The World Environment Day (WED) is observed every year on June 5 to raise awareness about forests and wider issues of environmental protection. The 2017 theme is ‘Connecting People to Nature’. It implores us to get outdoors and into nature, to appreciate its beauty and to take forward the call to protect the Earth that we share. The host country for the WED 2017 is Canada, where the official celebrations take place.

The resistance of metallic conductors e.g, platinum, increases with rise of  temperature . The increase in temperature results in a decrease of current which can be recorded in a galvanometer if the conductor is included in an electrical circuit. Thus the temperature can be known; platinum resistance thermometer is used generally for accurate scientific work. When two dissimilar metals are joined at the ends, and these ends are subjected to a difference of temperature, a current flows through the metals. Greater the difference of temperature , greater the current. So the curent strength can form the basis for measuring the difference in temperature. And when one of these temperatures is known, we can calculate the other.

• Cactus spines are also known as modified bud scales, which are also called modified leaves.

• Cactus spines occur in clusters in the axil of leaves.

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