Solar System

31.	Which word can best describe the shape of the earth?
	A. from the tetrahedron
	B. from orange
	C. from the equator
	D. from the oblate spheroid Option “D” is correct. The oblate spheroid, or oblate ellipsoid, is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis. It is the regular geometric shape that most nearly approximates the shape of the Earth. A spheroid describing the figure of the Earth or other celestial body is called a reference ellipsoid

32.	At what speed does the Earth revolve around the Sun in its orbit?
	A. 5 degrees per day
	B. 2 degrees per day
	C. 1 degree per day
	D. 3 degrees per day Option “C” is correct. The Earth also moves around the sun, by a little less than one degree per day (360/365.25 = 0.9856 degrees per day). So in 24 hours the direction of the Sun from the Earth has changed by almost a degree.

33.	The speed of rotation of the Earth around the Sun –
	A. Remains the same throughout the year.
	B. It is maximum when the Earth is closest to the Sun.
	C. It is maximum when the Earth is at the maximum distance from the Sun.
	D. It is minimum when the Earth is closest to the Sun. Option “B” is correct. As every part of earth takes a frill round with in 24 hours, the equator being the largest circle of latitude 0o, the speed is greater at the equator due to crossing the maximum distance per hour then at the Arctic circle.

34.	The speed of rotation of the earth is –
	A. 27 km/m
	B. 31 km/m
	C. 25 km/m
	D. 39.5 km/m Option “A” is correct. Earth makes a complete rotation in approximately 24 hours that is referred to as earth day. Rotation of Earth is constant but its speed differs with latitudes. The speed decreases, as we move towards northern and southern poles. At poles, the speed is so slow that it takes an entire day to spin. The closer to the equator, the faster the Earth’s rotation. The circumference of the Earth at the equator is 40,000 km. Earth completes one rotation in 24 hours. One hour is equal to 60 min so 24 hours $= 24 \times 60 = 1440$ min Speed of rotation $= D i s t a n c e T i m e = 40 , 000 1440 = 27.7$ approx. So, the Earth rotates approximately 27.7 kilometres in one minute at the equator.

35.	The diameter of the earth at the equator is approximately-
	A. 25,000 km
	B. 20,000 km
	C. 12,800 km
	D. 6,400 km Option “C” is correct. Earth’s diameter at the Equator is about 12,756 kilometers (7,926 miles). At the poles, the diameter is about 12,714 kilometers (7,900 miles). Earth’s equatorial bulge is about 43 kilometers (27 miles).

36.	In which month is the Earth at the maximum distance from the Sun during its orbit around the Sun?
	A. March
	B. July
	C. September
	D. January Option “B” is correct. The correct answer is Aphelion. The place at which the planet Earth is farthest from the sun is known as Aphelion. The distance of the aphelion between the Sun’s center and the Earth’s center is 152,097,700 km. The date of Aphelion is generally in the month of July.

37.	In which month is the sub-solar position of the earth?
	A. June
	B. January
	C. September
	D. March Option “B” is correct.

38.	Why are stars visible more in the east than in the west?
	A. The whole universe is rotating from east to west
	B. Earth orbiting the Sun
	C. The earth is rotating from east to west
	D. The earth is rotating from west to east Option “D” is correct. The Earth rotates on its own axis from West to East. Stars, thus appear to move from East to West, due to the relative motion of them with respect to the Earth.

39.	The spherical earth is flattened at the poles’ This is clearly proved by the fact –
	A. The weight of the earth is maximum at the poles and minimum at the equator.
	B. India of matter is minimum at the poles and maximum at the equator.
	C. The weight of matter is the same at the poles and at the equator.
	D. Matter loses its weight at the poles. Option “A” is correct. Earth is bulged out at equator and flattered at poles because of centripetal force. The earth spins at constant rate but rate of movement is different the equator is moving fastest and poles are not moving (ignoring the fact that earth is orbiting the sun). Because of this movement centrifugal force is pulling matter closer to equator which structure outwards giving earth slightly non-spherical shape.

40.	Earth rotates on its axis –
	A. East to West
	B. West to East
	C. North to South
	D. South to North Option “B” is correct. The Earth spins on its axis from west to east. The Coriolis force, therefore, acts in a north-south direction. The Coriolis force is zero at the Equator.

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