1. The summer and winter seasons in a year are caused by:
2 .Magnetic meridian is an imaginary:
Explain:-The magnetic meridian of a place can be defined as the vertical plane which passes through the imaginary line joining the magnetic north and the south poles.
This plane would intersect the surface of the earth in a longitude-like circle.
A magnetic needle, which is free to swing horizontally, would then lie in the magnetic meridian and the north pole of the needle would point towards the magnetic north pole.
Since the line joining the magnetic poles is titled with respect to the geographic axis of the earth, the magnetic meridian at a point makes an angle with the geographic meridian.
This is the angle between the true geographic north and the north shown by a compass needle. This angle is called the magnetic declination or simply declination.
The declination is greater at higher latitudes and smaller near the equator.
3. Advanced sunrise and delayed sun-set found in the sky are due to the phenomenon of:
Explain:- Refraction is phenomena of changing properties of waves when it passes through one substance.
Refraction of light changes the direction of ray of light when it propagates from one medium to another medium. These all phenomena occur due to refraction of light in different ways.
(A)Twinkling of stars:
This phenomenon appears to us because of continuous change in atmospheric density of layers of atmosphere due to sunlight. As atmosphere density increases or decreases in any of the atmospheric layers it causes change in intensity of light.
(B)Advanced sunrise and delayed sunset:
Before sunrise, sun’s rays pass through denser air to less dense air, causing rays to refract and appear to be coming from above the horizon whereas sun is below the horizon at this time. It looks like rays are coming straight from the sun and sunrise has happened. It is the reason behind the advance sunrise.
After sunset, the sun goes below the horizon. Sun’s rays pass through denser air to less dense air, it causes rays to refract and appear to be coming from above the horizon whereas the sun is below the horizon at this time. It looks like rays are coming straight from the sun and sunset has not happened. This is the reason for the delayed sunset.
(C) Blue colour of sky:
At the time between sunrise and sunset sun is closer to the position of the viewer than earlier. As sunlight consists of seven colors out of which blue light has the shortest wavelength, due to this blue light scatters more and the sky looks blue to us.
(D) Reddish colour of sky during sunrise and sunset:
At the time of sunrise and sunset sun is not closer to the position of the viewer than at other times. As sunlight consists of seven colors out of which red light has the highest wavelength, due to this red light scatters less and the sky looks reddish to us at a time of sunrise and sunset.
Note:Reason behind formation of rainbows in the sky during rainy days is also refraction. During rainy days water droplets are available in the atmosphere due to it sunlight goes through multiple refractions which causes a split of sunlight into seven colors.
4.The Circle of illumination divides Earth into two hemisphere known as
5.If the orbit of a planet is an ellipse, then what is the point at which the Sun is located called?
6. Which of the following planets take least time to complete one rotation on its axis???
7.Which of the following planets takes minimum time to take one revolution around the Sun?
8.Our solar system is a part of which galaxy?
Explain:- The solar system is a part of the Milky Way.
Key Points:
The Milky Way is a large spiral-shaped galaxy.
It is called the Milky Way because it appears as a soft glowing light of billions of stars.
Milky Way Galaxy formed 5 billion years after the Big Bang.
These stars are so far that they can be seen only in the constellation, not separately.
It takes about 250 million years to complete one revolution.
Additional Information
Andromeda is a spiral galaxy and also our closest neighbour.
Proxima centauri is the nearest star.
Mercury, Venus, Earth and Mars are called terrestrial planets
Jupiter, Saturn, Uranus and Neptune are called gaseous planets
9.Between which of the following two planet are the asteroids found?
10.Variations in the length of day time and night time from season to season are due to _____.
Explain:- Variations in the length of day and night time from season to season on the earth's surface is due to the axial tilt of earth's rotation axis with respect to its orbital axis. This causes variations in the intensity of Sun's rays falling at a given place over the span of a year leading to variations in day and night time.
11.The shortest day length that occurs in the Northern hemisphere is on _____.
Explain:- The shortest day and the longest night of the year in the northern hemisphere occur during winter solstice which is usually observed on the 22 nd of December . This is also the day of the longest day and the shortest night in the southern hemisphere.
12.Which one of the following statements is not correct?
13. Which of the following phenomenon is/are the effect of the rotation of the earth?
1. Apparent movement of the Sun the Moon and the stars.
2. Flatness of the poles and bulge at the equator.
3. Occurrence of sunrise, noon and sunset
4. Magnetic field of the earth
Select the correct answer by using the codes given below:
14. Which of the planet is also known as"Earth twin"?
15.Who among the following was the first to explain that the rotation of the earth on its own axis accounts for the daily rising and setting of the sun?
Explain:- Aryabhatta was the first to explain that the rotation of the earth on its own axis accounts for the daily rising and setting of the sun.
Key Points
Aryabhatta was born in India in 476 AD.
He also stated that the Earth was a spherical ball.
It takes around 23 hours, 56 minutes, and 4 seconds to rotate on its own axis.
Additional Information
India's first satellite was named after Aryabhatta.
It was launched with the help of USSR.
Rohini was the first satellite which was launched by India onboard SLV-3.
16.The earth nearest to the sun on -
17. Day and night are equal at the
18. In a solar or lunar eclipse, the region of earth shadow is divided into:
19. Which of the following planets has the shortest day?
20.The name of saturn largest moon is :
21.The earth rotate around it's axis from-
22. What is meant by the term "midnight sun" ?
Explain:-
The midnight sun is a natural phenomenon occurring in summer months at places north of the Arctic Circle and south of the Antarctic Circle where the sun remains visible at the local midnight.
Around the solstice (June 21 in the north and December 21 in the south) and given fair weather the sun is visible for the full 24 hours.
The number of days per year with potential midnight sun increases the farther towards either pole one goes.
23. Which of the following countries is known as the country of Midnight Sun?
Explain:-
The midnight sun is a natural occurrence that takes place in the summer period in the northern parts of the Arctic Circle and the southern parts of the Antarctic Circle.Midnight Sun is defined as the sun above the horizon at midnight in the arctic or antarctic summer. In the simplest terms, it means the sun appearing at midnight.
The Land of Midnight Sun:
The country, Norway has acquired the name of the Land of Midnight Sun, as Norway experiences the natural phenomena called the midnight sun because some parts of the country experience sunshine throughout the day. It is situated on the northern end of Europe. A small part of Norway is situated on the north side of the Arctic Circle and this northern part experiences the midnight sun during the summer.These places have the sun shining at midnight for some days. Places that are closest to the pole experience the highest number of days with the midnight sun.
Note :
The North Pole enjoys the midnight sun for half the year from March to September. Similarly, the South Pole has the midnight sun for half the year from September to March. Residents of Tromso, a city based in Norway enjoy sunshine throughout the day for almost 60 days. These northern regions enjoy the sun for almost 20 hours a day from mid-May to mid-July.
24. Of the following,Which is the largest world religion?
25.Which of the following statements is/are correct ?
(A) The earth is nearest to the Sun at Perihelion, which generally occurs on January 3.
(B) The earth is farthest away from the Sun at Perihelion, which generally occurs on July 4.
(C) The earth is farthest away from the Sun at Aphelion, which generally occurs on July 4.
(D) The earth is nearest to the Sun at Aphelion, which generally occurs on January 3.
Select the correct answer using the code given below :
26. Whivh of the following us correct about the solstice?
(1) It occur either of the two time of year at which the sun reaches its highest or lowest point in the sky at midday,marked by the longest and shortest days.
(2) The summer solstice take place on june 19 or 20
(3) The winter solstice takes place on December 21 or 22
27.Which one of the following statements is not correct?
28.'God particle' is
29.In sun, heat and light are produced by-
30.The fact that the planet moves around the sun, not in circles but in ellipse, was first demonstrated by
31.Which one of the following planets does not have a satellite?
32.What is a constellation?
33.On average, air contains________________% of water vapour.
34. Which of the following statements regarding the duration of day and night is correct?
Explain:-Due to the axial tilt of the Earth of an angle of approximately 23 degrees, there is variation in the duration of days and nights across the globe. This is due to difference in intensity of Sun's rays falling on different parts of the globe. This variation is minimum at the equator while it is maximum on poles
35.Eclipses occur due to which optical phenomena?
Explain:-Eclipses occur due to rectilinear propagation.
Key Points
An eclipse takes place when one heavenly body such as a moon or planet moves into the shadow of another heavenly body.
There are two types of eclipses on Earth: an eclipse of the moon and an eclipse of the sun.
Lunar Eclipse
Earth blocks the sunlight that normally is reflected by the moon in a lunar eclipse. A lunar eclipse can occur only when the moon is full.
Solar Eclipse
When the moon orbits Earth, it moves between the sun and Earth. When this happens, the moon blocks the light of the sun from reaching Earth
36.Which one of the following statements about temperature is correct?
37.The amount of water vapour present in the air is called?
Explain:-
Humidity: The amount of water vapour present in the air is called Humidity.
When the humidity of air is low, the rate of evaporation is high and water evaporates more readily. When the humidity of air is high, the rate of evaporation is low and water evaporates very slowly.
Humidity control: Silica and aluminium gels are used as adsorbents for removing moisture. These gels are used for controlling the humidity of rooms.
Temperature: It is the effect of heat energy that determines the thermal state of a given substance. it determines the degree of hotness or coldness of a substance.
Moisture: The amount of water molecule present in the substance is called moisture.
38. The twinkling of stars is due to atmospheric:
39.In which of the following the lunar eclipse occur?
40.Which of the following statements relating to solar is/are correct?
1.Venus and Uranis rotate opposite to the direction of rotation of earth
2.Venus is the nearest planet to earth
Select the correct answer using the code given below:
41. What is the primary cause of tides in the sea?
Explain:- Tides in the sea are primarily due to the gravitational pull of the moon and the sun on the Earth's oceans. The moon's gravity is stronger than the sun's gravity, so it has a greater effect on tides. As the moon orbits around the Earth, its gravitational force pulls water towards it, causing a bulge in the ocean on the side of the Earth facing the moon.
At the same time, there is another bulge on the opposite side of the Earth due to the centrifugal force created by the rotation of the Earth-moon system. This causes two high tides and two low tides each day. The sun also has a similar effect on tides, but it is much weaker than the moon's influence. Other factors that can affect tides include the shape of coastlines and ocean basins, as well as weather conditions such as storms and winds.
42.Which has a greater effect on tides, the moon or the sun?
43.How many high tides and low tides occur each day due to the moon's gravitational pull?
44.What other factors can affect tides besides the gravitational pull of the moon and sun?
45.Which of the following is NOT a weather condition that can affect tides?
46. What is an ocean current?
47.What causes ocean currents?
Explain:-
Factors Influencing Nature and Movement of Ocean Currents:
1. Factors related to the earth’s rotation: Gravitational force and force of deflection.
2. Factors originating within the sea: Atmospheric pressure, winds, precipitation, evaporation and insolation.
3. Factors originating within the sea: Pressure gradient, temperature difference, salinity, density and melting of ice.
4. Factors modifying the ocean currents: Direction and shape of the coast, seasonal variations and bottom topography.
48.How do ocean currents affect climate?
49. What is upwelling?
50.What is El Niño/ La Niña?
51.How do ocean currents affect marine life?
52.Which current out of the following flows in the Indian Ocean?
Explain:-Important Points
Currents in the Indian Ocean include the following:
1.The North-East Monsoon Drift
2.The South West Monsoon Drift
3.North Equatorial Current (Warm)
4.South Equatorial Current (Warm)
5.Somali Current (Cold)
6.Mozambique Current (Warm)
7.Madagascar Current (Warm)
8.Agulhas Current (Warm)
9.West Australian Current (Cold)
Additional Information
The Florida Current is a thermal ocean current that flows from the Straits of Florida around the Florida Peninsula and along the southeastern coast of the United States.
Canary Current, part of a clockwise-setting ocean-current system in the North Atlantic Ocean.
Oyashio Current or the Kurile current is the western boundary current in the subpolar gyre of the North Pacific.
It originates in the Bering Sea and flows south-west off the Kuril Islands to meet the Kuroshio Current east of northern Japan
53. Consider the following factors:
1.Rotation of the earth
2.Air pressure and wind
3.Density of ocean water
4.Revolution of the earth
54. Star twinkle but planets do not twinkle because
55.The constellation 'Sapta Rishi' is known to Westerners as
56. In an eclipse where the Moon,sun and earth are involved,they are nearly in a _______________
57. A total eclipse occurs when the observer is within the____________
58.Total Solar eclipse occur when
Explain:-
A Solar eclipse occurs when the moon comes in between the earth and the sun.
It leaves a moving region of shadow on the earth's surface.
Eclipse can be classified into four types annular, total, partial, and hybrid.
An annular Solar eclipse occurs when the moon completely covers the sun.
A total solar eclipse occurs when the new moon comes between the sun and the earth casting the darkest part of a shadow on Earth.
In a total solar eclipse, the moon covers the disc of the sun entirely.
It is called the total solar eclipse because at the maximum point of the eclipse the sky goes dark.
Lunar Eclipse
Earth is between sun and moon OR Blocks sunlight going from Sun to Moon
Solar Eclipse
Moon is between Sun and Earth
Blocks sunlight going from Sun to Earth