I hope that by 2050 the entire solar system will have been explored and mapped by flotillas of tiny robotic craft.
–Martin Rees
EARTH
Have you .
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For Learners:
DIYHA (do it yourself home activity):
1. Practical 1 (Insolation): Understand how the heat density changes with straight and angular light beams.
2. Take the School Exam Quiz on this topic, log-in here.
For Educators & Researchers:
1. Devise an experiment to
ऋषि उवाच
1. कोणे नता पृथ्वी मुख्य कारणं । सूर्यात दूरी समुद्रः च गौण।
2. k
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EARTH
Do you know t
1. Rotation
The earth rotates
For Learners:
DIYHA (do it yourself home activity):
1. Practical 1 (Thought Exercise): How would you determine the length of day in each of the following cases:
(i) Imagine
2. Take the School Exam Quiz on this topic, log-in here.
For Educators & Researchers:
1. Write a paper on how the seasons of earth change in different epochs due to earth’s axial precession (nutation).
ऋषि उवाच
1. ok
2. कोणे नता पृथ्वी मुख्य कारणं । सूर्यात दूरी समुद्रः च गौण।
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ECLIPSES
Do you know
1. Solar Eclipse
It is
For Learners:
DIYHA (do it yourself home activity):
1. Practical 1 (Earth-Moon distance): There are two methods.
2. Take the School Exam Quiz on this topic.
For Educators & Researchers:
1. Write down
ऋषि उवाच
1. ok
2. कोणे नता पृथ्वी मुख्य कारणं । सूर्यात दूरी समुद्रः च गौण।
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ESTIMATING TEMPERATURE OF SUN
GRAVITY GLOBE
LEADING ARTICLES
Do you know
1. Solar Eclipse
The .
2. Lunar Eclipse
ok
QUIZ
Each of the following questions has four answer options: a, b, c, d. Choose the correct one.
1. If you are situated anywhere at the Tropic of Cancer then your shadow can never point in this direction:
(a) North
(b) East
(c) South
(d) West
2. Consider the factors causing change of seasons on earth:
(i) Distance from the sun.
(ii) Rotation of earth around sun.
(iii) Precision of earth’s axis.
(iv) Tilt of earth’s axis.
Which of the following are the main factors responsible for change of seasons on earth?
(a) (i) and (ii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
3. The maximum possible range of Sun’s declination is:
(a) 23.45º
(b) 45º
(c) 46.9º
(d) 90º
5. The angle of the shadow formed by Sun at the flat earth’s surface is equal to the angle of:
(a) Latitude
(b) Longitude
(c) Inclination
(d) Declination
6. Match the following:
(a) 23:56:04
(b) 23:45
(c) 365:05:48:56
(d) 40,075 and 40,008
(e) 1.07 lakh and 1675
(f) 15.2 cr and 14.7 cr
(g) 4.05 lk and 3.60 lk (km)
(h) 8.28 lk and 25 cr
(i) 110.6 to 111.7
(j) 111.3 to zero
(k) 15′
(l) 0.257 and 3.89
(m) 1.97
—
(A) apogee and perigee distance between earth & moon (in km). The difference is 45k km.
(B) speed (km/hr) at which solar system is hurtling through MW galaxy and the duration (in earth years) of 1 revolution (galactic year).
(C) apogee and perigee distance between earth & sun (in km). The difference is 50 lakh km.
(D) average speed (in km/hr) of earth’s revolution and earth’s rotation (at equator)
(E) equatorial & polar circumference in km
(F) length of year in d:h:m:s
(G) angle of tilt of the earth’s axis to the plane of ecliptic
(H) length of sidereal day in h:m:s
(I) Distance per degree of Latitude (in km) at equator and at poles.
(J) Distance per degree of Longitude (in km) at equator and at poles. Away from the equator, this distance is 111.3 x cos(lat.)
(K) 15 minutes of arc variation occurs per day and per minute in Latitude and Longitude respectively.
(L) Angular change (in degrees) of Sun’s declination (i.e in the angle between equator and sun rays), and Number of days required for 1º change in Sun’s declination.
(M) This is the factor you have to multiply with your height (in feet) to find the distance to horizon (in km)
BMT (Bharat Mean Time) is a convenient reference for Time Difference from India
(Lahore of undivided Bharat taken as reference because of whole number with respect to GMT/ UTC).
| CITY/ COUNTRY | BMT + | GMT/UTC + |
| Alaska | -13 | -8 |
| California, Seattle, Vancouver | -12 | -7 |
| Salt Lake City | -11 | -6 |
| Peru, Colombia | -10 | -5 |
| Chicago, Texas, Mexico City | -10 | -5 |
| Florida, WDC, New York, Montreal | -9 | -4 |
| Chile | -9 | -4 |
| Rio de Janerio | -8 | -3 |
| GMT (London) | -5 | 0 |
| Italy, Germany, Norway | -3 | 2 |
| Egypt, S. Africa | -3 | 2 |
| Turkey, Moscow | -2 | 3 |
| Dubai | -1 | 4 |
| Kazakhastan | 0 | 5 |
| LAHORE | 0 | 5 |
| INDIA | 0.5 | 5.5 |
| Thailand | 2 | 7 |
| Indonesia | 3 | 8 |
| Singapore, Malaysia | 3 | 8 |
| China | 3 | 8 |
| Perth | 3 | 8 |
| Tokyo | 4 | 9 |
| Sydney | 5 | 10 |
| NZ | 7 | 12 |