Gnav 2

Which statement about the duration of daylight is true?

• Close to the solstices the influence of latitude on the duration of daylight is at its smallest.

• Close to the equinoxes the influence of latitude on the duration of daylight is at its smallest.

• In summer the length of the period of daylight decreases with increasing latitude.

• On September 10th the duration of daylight is longer on the Southern Hemisphere than on the Northern Hemisphere.

The term 'sidereal' is used:

• to describe how two positions of heavenly bodies are located sideways on the sky.

• to describe conditions with reference to the Moon.

• to describe a situation or relationship concerning the stars.

• to describe the time interval between two successive transits of the real apparent Sun at the same meridian.

'Apparent Time' is:

• the correct time, as it appears on our watches and clocks.

• the average time, calculated from the movements of the Sun and the stars.

• based on the time of transit of the apparent Sun.

• the time that is apparent to everybody: in other words the official time.

At 0000 Local Mean Time of an observer:

• the mean Sun is in transit with the observer's anti-meridian.

• the mean Sun is in transit with the observer's meridian.

• the apparent Sun is in transit with the observer's meridian.

• the apparent Sun is in transit with the observer's anti-meridian.

An approximate equation for calculation conversion angle is:

• CA = 0.5 x dlong x sin(mean lac)

• CA = dlong x sin(mean lac) x sin(long)

• CA = (dlong - dlac) x 0.5

• CA = 0.5 x dlac x sin(mean lac)

If you are flying along a parallel of latitude, you are flying:

• a great circle track.

• on a North-South track.

• on a track which is constantly changing direction.

• a rhumb line track.

The circumference of the Earth is approximately:

• 43200 NM

• 10800 NM

• 21600 NM

• 5400 NM

You are flying from A (30°S 20°E) to B (30°S 20°W). What is the RL track from A to B?

• 250°(T)

• 270°(T)

• 290°(T)

• 300°(T)

Consider the following statements on the properties of a great circle:

• the great circle will maintain their initial true direction.

• the parallels of latitudes are all great circles.

• the great circle running through two positions on the surface of the Earth, is the shortest distance between these two positions.

• all answers are correct.

Consider the following statements:

• the exact length of a 1' of arc is shorter at high altitude than at sea level, when the arc is observed from the center of the Earth.

• in any position on the surface of the Earth, the length of 1' of arc east/west is equal to the length of 1' of arc north/south in the same position on a perfect sphere.

• the exact length of a 1' of Great Circle arc varies a little from position to position because the Earth radius vary.

• all statements are correct.