Karnataka PSI test series 2018 is the one of the popular initiative of StudyVillae. In this section we provide the key answers and explanations for each of the questions in the tests. Aspirants should check their answers with the keys provided and should revise accordingly.
PSI-103 Key Answers
Q.1) How many planets are there in our solar system?
- 7
- 8
- 9
- 10
Q 1) solution (2)
There are eight planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The four inner solar system planets (Mercury, Venus, Earth, and Mars) fall under the category of terrestrial planets; Jupiter and Saturn are gas giants (giant plants composed mostly of hydrogen and helium) while Uranus and Neptune are the ice giants (containing mainly elements heavier than hydrogen and helium) Pluto, a dwarf planet.
Q.2) Which is the smallest planet in our solar system?
- Earth
- Mercury
- Venus
- Mars
Q 2) solution (2)
The smallest planet in regard to both mass and volume is Mercury — at 4,879 km across and 3.3010 x 1023 kg, this tiny world is nearly 20 times less massive than Earth, and its diameter is about 2½ times smaller. In fact, Mercury is closer in size to our Moon than to Earth.
Q.3) Which is the largest planet in our solar system?
- Jupiter
- Saturn
- Uranus
- Neptune
Q 3) solution (1)
The largest planet in our solar system by far is Jupiter, which beats out all the other planets in both mass and volume. Jupiter’s mass is more than 300 times that of Earth, and its diameter, at 140,000 km, is about 11 times Earth’s diameter. (Jupiter’s Great Red Spot, even at its current diminished size, spans 15,900, just over a full Earth diameter.) Jupiter is 2½ times more massive than the rest of the planets in the solar system combined. Despite its bulk, though, Jupiter has a fast rotation period of just 10 hours!
Q.4) Which is the nearest planet to the sun in our solar system?
- Mercury
- Mars
- Earth
- Venus
Q 4) solution (1)
Mercury is nearest to the sun. It takes only about 88 days to complete one round along its orbit. Venus is considered as ‘Earth’s-twin’ because its size and shape are very much similar to that of the earth.
Q.5) Which planet is called blue planet in our solar system?
- Mercury
- Mars
- Earth
- Venus
Q 5) solution (3)
From the outer space, the earth appears blue because its two-thirds surface is covered by water. It is, therefore, called a blue planet.
Q.6) The prime meridian passes through which city and country?
- United Kingdom
- France
- Spain
- Algeria
Q 6) solution (1)
All countries decided that the count should begin from the meridian which passed through Greenwich, where the British Royal Observatory is located i.e in United Kingdom. This meridian is called the Prime Meridian. Its value is 0° longitude and from it we count 180° eastward as well as 180° westward. The Prime Meridian and 180° meridian divide the earth into two equal halves, the Eastern Hemisphere and the Western Hemisphere. Therefore, the longitude of a place is followed by the letter E for the east and W for the west. It is, however, interesting to note that 180° East and 180° West meridians are on the same line.
Q.7) What is the latitudinal value of the Tropic of Cancer?
- 23.5 North
- 23.5 South
- 66.5 North
- 44.5 South
Q 7) solution (1)
Besides the equator (0°), the North Pole (90°N) and the South Pole (90° S), there are four important parallels of latitudes–
- Tropic of Cancer (23½° N) in the Northern Hemisphere.
- Tropic of Capricorn (23½° S) in the Southern Hemisphere.
- Arctic Circle at 66½° north of the equator.
- Antarctic Circle at 66½° south of the equator.
Q.8) How many minutes are in a latitude degree?
- 5 minutes
- 4 minutes
- 15 minutes
- 6 minutes
Q 8) solution (2)
As the earth rotates from west to east, those places east of Greenwich will be ahead of Greenwich time and those to the west will be behind it (Figure 2.8). The rate of difference can be calculated as follows.
The earth rotates 360° in about 24 hours, which means 15° an hour or 1° in four minutes.
Thus, when it is 12 noon at Greenwich, the time at 15° east of Greenwich will be 15 × 4 = 60 minutes, i.e., 1 hour ahead of Greenwich time, which means 1 p.m.
But at 15° west of Greenwich, the time will be behind Greenwich time by one hour, i.e., it will be 11.00 a.m. Similarly, at 180°, it will be midnight when it is 12 noon at Greenwich.
Q.9) How many days earth takes to complete the revolution of the sun?
- 365 days 3 hours
- 365 days 6 hours
- 365 days 9 hours
- 365 days 12 hours
Q 9) solution (2)
The second motion of the earth around the sun in its orbit is called revolution. It takes 365¼ days (one year) to revolve around the sun. We consider a year as consisting of 365 days only and ignore six hours for the sake of convenience. Six hours saved every year are added to make one day (24 hours) over a span of four years. This surplus day is added to the month of February. Thus, every fourth year, February is of 29 days instead of 28 days. Such a year with 366 days is called a leap year.
Q.10) How many continents are there?
- 7
- 6
- 8
- 9
Q 10) solution (1)
There are seven major continents. These are separated by large water bodies. These continents are – Asia, Europe, Africa, North America, South America, Australia and Antarctica. Look at the map of the world and notice that the greater part of the land mass lies in the Northern Hemisphere.
Q.11) Which is the third largest continent?
- Asia
- Europe
- Africa
- North America
Q 11) solution (4)
North America is the third largest continent of the world. It is linked to South America by a very narrow strip of land called the Isthmus of Panama. The continent lies completely in the Northern and Western Hemisphere. Three oceans surround this continent.
Q.12) Which is the largest ocean?
- Pacific Ocean
- Atlantic Ocean
- Indian Ocean
- Arctic Ocean
Q 12) solution (1)
The Pacific Ocean is the largest ocean. It is spread over one-third of the earth. Mariana Trench, the deepest part of the earth, lies in the Pacific Ocean. The Pacific Ocean is almost circular in shape. Asia, Australia, North and South Americas surround it. Look at the map and find out the location of the continents around the Pacific Ocean.
Q.13) Which is the largest Gas form composed in our Atmosphere?
- Oxygen
- Nitrogen
- Argon
- Carbon dioxide
Q 13) solution (2)
The atmosphere is composed mainly of nitrogen and oxygen, which make up about 99 per cent of clean, dry air. Nitrogen 78 per cent, oxygen 21 per cent and other gases like carbon dioxide, argon and others comprise 1 per cent by volume. Oxygen is the breath of life while nitrogen helps in the growth of living organisms. Carbon dioxide, though present in minute amount, is important as it absorbs heat radiated by the earth, thereby keeping the planet warm. It is also essential for the growth of plants.
Q.14) what is the total land covered by India?
- 3,287,469 sq km
- 3,287,569 sq km
- 3,285,469 sq km
- 3,286,469 sq km
Q 14) solution (1)
India has an area of about 3.287 469 sq. km. The north-south extent from Kashmir to Kanyakumari is about 3,200 km. And the east-west extent from Arunachal Pradesh to Kuchchh is about 2,900 km.
Q.15) Between which latitudes and longitudes India is located?
- 8°3′ to 37°6′ north, 68°7′ to 97°20′ east
- 8°4′ to 37°7′ north, 66°7′ to 97°25′ east
- 8°4′ to 37°6′ north, 68°7′ to 97°25′ east
- 8°2′ to 37°6′ north, 68°7′ to 97°35′ east
Q 15) solution (3)
India is located in the northern hemisphere. The Tropic of Cancer (23°30’N) passes almost halfway through the country (Figure 7.2). From south to north, main land of India extends between 8°4’N and 37°6’N latitudes. From west to east, India extends between 68°7’E and 97°25’E longitudes. If we divide the world into eastern and western hemispheres, which hemisphere would India belong to? Due to great longitudinal extent of about 29°, there could be a wide difference in local time of places located at two extreme points of India.
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