We 'n' Our Society - 6.pdf - School Books Publishers India

6. What is the importance of 82º30E ' longitude in India?Ans. In India 82º 30'E (82½ºE) has been accepted as the standard Meridianfor the whole country. This time is Indian Standard Time (IST). TheIST is ahead of GMT by 5 hours 30 minutes.7. What is the difference between longitude and latitude?Ans. Longitude Latitude1. A longitude is an imaginary A latitude is an angular fromline drawn joining the two poles. the equator.2. These are called Meridians. These are called parallels.3. Longitudes divide the earth into Latitudes divide the earth intoeastern and western hemisphere. northern and southernhemisphere.8. What is the purpose of having time zone?Ans. The world was divided into 24 time zones in 1884. Each time zone hasa longitudinal extent of 15 degrees or one hour. Every country sets itstime according to the time zone it falls. The standard time of everyzone is set exact number of hours ahead or behind the GMT.9. What is the relationship between longitude and time? Verify itwith examples.Ans. The rotation of the earth gives us the measure of the day. Everymeridian faces the sun once in a day. When the meridian is facing thesun, it is the noon at that place. The places east of a given longitude willhave the sunrise first. For example – Tokyo experiences sunrise beforeLondon and London experiences sunrise before New York.In other words, we can say that the earth rotates through 15 degrees oflongitude in one hour and 1 degree of longitude in 4 minutes.10. Why does a country need Standard Time?Ans. The local time of a place is based on the meridian of that place. Therewould be confusion, if all places on different meridians, follow theirown local time So every country in the world, has its own Centralmeridian. This time is taken as the Standard time for the entire regionor the country.3. ROTATION AND REVOLUTIONOF THE EARTHExercisesA. Tick ( 3) the correct answer :1. The movement of the Earth around the sun is called :(a) Rotation(b) Revolution3(c) Orbit(d) None of them2. The minimum speed of Earth's rotation is at :(a) Equator(b) Poler3(c) Both of them(d) None of themHorizon Press 8We 'n' Our Society – 6