D. Give reasons for the following:
1. Latitudes and Longitudes are always expressed in
angles.
2. Large countries have many time zones.
3. The International Date Line is not a straight line like
other longitudes.
4. A person gains time as he travels towards east.
5. The intervals between successive parallels are
constant.
6. A person travelling from Mumbai to London has to
alter his watch.
7. The difference between I.S.T. and the G.M.T. is
5 hours and 30 minutes.
Answers
1. Latitudes and longitudes, like angles, are expressed in terms of degrees. Degrees are a way to measure angles. They tell us how much of a full rotation (a circle, in essence) the angle makes up. There are 360 degrees in a circle.
2. Time zones are based on the fact that it takes one hour for the earth to rotate 15 degrees on its axis. This means that if the sun is at its zenith at some location (local noon—when it is at highest part of its arc across the sky) it is an hour later 15 degrees of longitude east of that point and an hour earlier 15 degrees of longitude west of that point.
That means that large countries that span more than 30 degrees of longitude usually have different time zones. Although there are a couple of countries that ignore this and have only one time zone for political reasons.
3.It is International Date Line which is drawn at 180 degree longitude to determine the date which is passed through the Arctic Oceans, Bering Strait, Pacific Ocean, Antarctica, Fiji, Tonga and other islands.If we see this imaginary line, then we found, it is not straight but zig-zag line.
4. don't know
5.This is a profound question. It was an assumption in geometry from Euclid onwards (even though the Greeks etc did understand geometry on a spherical surface). If the distance between parallels is constant then we have standard Euclidian geometry. But, from the 19th century onwards it became clear that perfectly valid geometries could be constructed where the idea of parallel lines disappears. If you draw 2 straight lines on a sphere then they will always intersect if they are long enough (if you’re worried about what it means to draw a straight line on a sphere then that’s good). Other geometries can be found where two lines that appear parallel at some point will become further apart as you move away from that point in either direction. This is hyperbolic geometry. These geometries are a fascinating subject and are fairly easy to wrap your head around in two dimensions because we can draw pictures
6. Because fashion trends are different between the two places. For example, in London, everybody wears a Timex watch, even the Queen. In Mumbai, people are more likely to wear Rolexes and Breitlings, so if you want to fit in, you'll have to change your watch before you travel.
7. Indian Standard time is the time observed throughout India and Sri lanka, and GMT or Greenwich Mean Time is the clock time at the Royal Observatory in Greenwich, London. Indian Standard Time is 5 hours and 30 minutes ahead of Greenwich Mean Time.