Solar Energy Multiple Choice Questions on “Solar Day Length”.
1. What is solar noon?
a) Time of the day at which sun’s rays are perpendicular to a given line of longitude
b) Time of the day at which sun’s rays are parallel to a given line of longitude
c) Time of the day at which sun’s rays are perpendicular earth’s surface
d) Time of the day at which sun’s rays are parallel to earth’s surface
Answer: a
Clarification: Solar noon is defined as the time of the day at which sun’s rays are perpendicular to a given line of longitude. It is important to note that solar noon does not occur simultaneously at every location on earth. Hence the phrase, “give line of longitude”.
2. How does the solar noon vary with every 15 degrees of longitude east of a given longitude?
a) Solar noon occurs one hour late with every 15 degrees of longitude east of a given longitude
b) Solar noon occurs one hour earlier with every 15 degrees of longitude east of a given longitude
c) Solar noon occurs does not vary with longitude
d) Solar noon occurs half hour late with every 15 degrees of longitude east of a given longitude
Answer: b
Clarification: Solar noon varies with longitude but it is important to mention the reference longitude for correct calculation. It occurs one hour late with every 15 degrees of longitude east of a given longitude. This can be used to estimate the time of different regions.
2. How does the solar noon vary with every 15 degrees of longitude west of a given longitude?
a) Solar noon occurs one hour later with every 15 degrees of longitude west of a given longitude
b) Solar noon occurs one hour earlier with every 15 degrees of longitude east of a given longitude
c) Solar noon occurs one hour later with every 15 degrees of longitude west of a given longitude
d) Solar noon occurs half hour later with every 15 degrees of longitude west of a given longitude
Answer: c
Clarification: To calculate solar noon, it is important to mention the reference longitude. Once the reference is known, solar noon occurs one hour later with every 15 degrees of longitude west of a given longitude.
4. What is a solar day?
a) One complete revolution of sun around moon
b) One complete revolution of earth around sun
c) One complete revolution of moon around earth
d) One complete revolution of sun around earth
Answer: d
Clarification: Though the earth revolves around the sun and rotates about its own axis, a solar day is measured with respect to an observer on earth. Hence, a solar day is defined as one complete revolution of sun around earth.
5. What is a sidereal day?
a) Time taken by earth to rotate about its axis for distant stars to appear fixed
b) Time taken by earth to rotate about its axis for sun to appear fixed
c) Time taken by earth to rotate about its axis for distant stars to be moved by 1 degree
d) Time taken by earth to rotate about its axis for distant stars to be moved by 0.5 degrees
Answer: a
Clarification: Sidereal day is the time taken by earth to rotate about its axis for distant stars to appear fixed. Time taken by earth to rotate about its axis for sun to appear fixed is solar day.
6. Solar day is ______ sidereal day.
a) 4 min shorter than
b) 4 min longer than
c) 10 min shorter than
d) 10 min longer than