The Prime Meridian does not pass through which one of the following African countries?
- (a)Morocco
- (b)Algeria
- (c)Mali
- (d)Ghana
Correct — A, Morocco. Running south from Greenwich the Prime Meridian crosses the Mediterranean and enters Africa in Algeria, then passes through Mali, Burkina Faso, Togo and Ghana before reaching the Atlantic in the Gulf of Guinea. Morocco lies entirely west of the zero degree line, so the meridian misses it — and Morocco is the only one of the four options it does not cross.
- (b)Algeria — Algeria is where the Prime Meridian makes landfall in Africa; the line runs south through the country to the border with Mali near Bordj Badji Mokhtar.
- (c)Mali — The meridian continues out of Algeria into Mali, passing close to Gao, so Mali is crossed.
- (d)Ghana — Ghana is the last country the line crosses before the Atlantic; the meridian cuts across Lake Volta and reaches the coast near Tema.
The Prime Meridian is the zero degree line of longitude, from which all other longitudes are measured east and west, and from which Greenwich Mean Time is reckoned. Its African stretch is worth memorising because so few countries lie on it, which makes it easy exam material.
The natural trap is to think of North Africa as a block and assume the meridian sweeps across Morocco on its way south. It does not — Morocco is the north-western corner of Africa and sits west of zero degrees, while the line enters the continent further east, through Algeria. Remember that only five African countries are crossed, in the order Algeria, Mali, Burkina Faso, Togo, Ghana.
- In Africa the Prime Meridian crosses Algeria, Mali, Burkina Faso, Togo and Ghana, and no others.
- Morocco lies wholly west of the zero degree line, so the meridian does not touch it.
- The meridian's Ghanaian stretch runs across Lake Volta and reaches the coast near Tema, in the Gulf of Guinea.
- The satellite-based reference meridian used today lies about 100 metres east of the historic transit line marked at the Royal Observatory, Greenwich.
- Assuming any North African country on the Mediterranean must be on zero degrees.
- Mixing up the countries on the Prime Meridian with those on the Equator — Ghana is near both but the Equator misses it.
A negative map-recall item; the safest route is to hold the list of five crossed African countries in memory.
When there is noon at the G.M.T. meridian, people at another place of the Earth are taking their 6 o'clock morning tea. The longitude of the place is
- (a) 17° 30′ E
- (b) 7° 30′ W
- (c) 172° 30′ E
- (d) 90° W
Answer(d) 90° W
Uses the same Greenwich zero degree line, but from the time side — longitudes are counted east and west of the Prime Meridian at 15 degrees per hour.
If it is 12.00 Noon in India, on which meridian will it be 7.00 am of the same day?
- (a) 7.5 degree E. Longitude
- (b) 7.5 degree W. Longitude
- (c) 75 degree E. Longitude
- (d) 75 degree W. Longitude
Answer(a) 7.5 degree E. Longitude
Another NDA item that turns on longitudes measured east and west of the Prime Meridian, here converted into clock time.
- practice — not a real PYQ
Which one of the following African countries is crossed by both the Prime Meridian and the Equator?
- (a)Ghana
- (b)Algeria
- (c)None of these
- (d)Mali
Answer(c) None of these — the Prime Meridian leaves Africa at Ghana, well north of the Equator, and enters the Gulf of Guinea before reaching zero degrees latitude.
- practice — not a real PYQ
Where does the Prime Meridian make landfall in Africa?
- (a)Morocco
- (b)Tunisia
- (c)Algeria
- (d)Libya
Answer(c) Algeria — the line crosses the Mediterranean and enters the continent through Algeria.