Which one of the following longitudes is the standard meridian of India?
- (a)83°30' E
- (b)82°30' E
- (c)82°30' W
- (d)83°30' W
Correct — B, 82°30' E. India keeps a single clock set to the local mean time of 82 degrees 30 minutes east longitude, a line that passes near Mirzapur in Uttar Pradesh. The arithmetic is fixed: the Earth turns 360 degrees in 24 hours, so 15 degrees of longitude is one hour and 82.5 divided by 15 gives 5.5 — Indian Standard Time is therefore UTC plus five and a half hours. The two western options can be dismissed without any calculation, since the whole of India lies east of Greenwich, between roughly 68 and 97 degrees east.
- (a)83°30' E — 83°30' E is a plausible-looking near miss, but it would put the country's clock at 5 hours 34 minutes ahead of Greenwich, which is not the half-hour offset India actually keeps.
- (c)82°30' W — 82°30' W runs through the Caribbean and the eastern United States. India lies wholly in the eastern hemisphere, so a western meridian cannot be its standard.
- (d)83°30' W — 83°30' W is wrong for the same reason, and carries the wrong number of degrees as well.
A standard meridian is chosen so that one clock can serve a whole country. India's mainland spans about 30 degrees of longitude, which is nearly two hours of real solar time between Gujarat and Arunachal Pradesh, so a single reference line is a compromise; 82°30' E was picked because it runs close to the middle of the country. Indian Standard Time was adopted on 1 January 1906. The half-hour offset comes straight from the meridian, since 82.5 degrees is not a whole multiple of 15.
Two of the four options can be struck out on the hemisphere alone, which leaves a straight choice between 82 and 83 degrees 30 minutes east. The check is the offset every candidate already knows: five and a half hours multiplied by 15 gives 82.5, and nothing else. The recurring proposal to give the north-east its own time zone rests on the same arithmetic — sunrise at Dibrugarh comes almost two hours before sunrise at Dwarka, and the country still runs on one clock.
- India's standard meridian is 82°30' E, passing near Mirzapur in Uttar Pradesh.
- Indian Standard Time is UTC plus 5 hours 30 minutes, because 82.5 degrees divided by 15 degrees per hour is 5.5.
- Fifteen degrees of longitude equals one hour; one degree equals four minutes.
- Indian Standard Time was adopted on 1 January 1906.
- The Indian mainland extends from about 68°7' E to about 97°25' E, roughly two hours of solar time.
The offset and the meridian are the same fact written two ways, so either one recovers the other in the exam hall.
- Confusing the standard meridian with the Tropic of Cancer, which is a line of latitude at 23°30' N.
- Reading the minutes as decimals — 82°30' is 82.5 degrees, not 82.30.
- Forgetting to check the hemisphere; two of the four options here are in the west.
As a direct question on the standard meridian, or through the time-offset route by asking what the local time would be at a given longitude.
Along which one of the following meridians did India experience the first light of the sunrise of the new millennium?
- (a) 2° 30′ W
- (b) 82° 30′ E
- (c) 92° 30′ W
- (d) 92° 30′ E
Answer(d) 92° 30′ E
The standard meridian appears there as the trap. That question asks where the sun rises first, which is the eastern edge of the country, not the line the clocks are set by.
Which of the following statements is/are correct with respect to Time Zone in India? 1. There is one standard time for the whole country. 2. Andaman and Nicobar Islands and Lakshadweep Islands have different Time Zones. 3. Indian Standard Time (IST) is five and half hours behind GMT. Select the correct answer using the code given below:
- (a) 1 only
- (b) 2 only
- (c) 1 and 2 only
- (d) 1 and 3 only
Answer(a) 1 only
The same clock, tested on its consequences later the same year. Note the direction in its third statement — India is five and a half hours ahead of Greenwich, not behind, which follows from the meridian being east.
- practice — not a real PYQ
The standard meridian of India passes through which one of the following states?
- (a)Bihar
- (b)Uttar Pradesh
- (c)Maharashtra
- (d)Karnataka
Answer(b) Uttar Pradesh — 82°30' E runs near Mirzapur, and the line also crosses several states to its south.
- practice — not a real PYQ
If a place lies on 90° E, its local mean time will be ahead of Greenwich Mean Time by
- (a)5 hours 30 minutes
- (b)6 hours
- (c)6 hours 30 minutes
- (d)5 hours
Answer(b) 6 hours — 90 divided by 15 is 6, using the rule that 15 degrees of longitude equals one hour.