Q.1 Which planet in our solar system has the fastest orbital speed around the Sun?
Earth
Mercury
Jupiter
Venus
Explanation - Mercury is closest to the Sun, and according to Kepler's laws, planets closer to the Sun move faster in their orbits.
Correct answer is: Mercury
Q.2 What is the primary component of the Sun's energy production?
Nuclear fission
Nuclear fusion
Chemical combustion
Gravitational contraction
Explanation - The Sun produces energy by fusing hydrogen nuclei into helium in its core, releasing enormous amounts of energy.
Correct answer is: Nuclear fusion
Q.3 Which of the following celestial objects is classified as a dwarf planet?
Mars
Pluto
Venus
Neptune
Explanation - Pluto was reclassified as a dwarf planet in 2006 because it does not clear its orbit of other debris.
Correct answer is: Pluto
Q.4 What type of galaxy is the Milky Way?
Elliptical
Spiral
Irregular
Lenticular
Explanation - The Milky Way has a central bulge with spiral arms, classifying it as a barred spiral galaxy.
Correct answer is: Spiral
Q.5 Which planet has the strongest magnetic field in the solar system?
Earth
Jupiter
Saturn
Neptune
Explanation - Jupiter's rapid rotation and liquid metallic hydrogen interior create the strongest planetary magnetic field in the solar system.
Correct answer is: Jupiter
Q.6 Which layer of the Sun is visible to the naked eye?
Core
Radiative zone
Photosphere
Corona
Explanation - The photosphere is the Sun's visible surface, emitting most of the light we see.
Correct answer is: Photosphere
Q.7 What phenomenon causes a star to appear to twinkle when viewed from Earth?
Star's rotation
Earth's magnetic field
Atmospheric refraction
Star's pulsation
Explanation - The Earth's atmosphere bends light unevenly, causing stars to appear to twinkle.
Correct answer is: Atmospheric refraction
Q.8 Which spacecraft was the first to land humans on the Moon?
Apollo 11
Sputnik 1
Voyager 1
Challenger
Explanation - Apollo 11 carried Neil Armstrong and Buzz Aldrin to the Moon in 1969, marking the first human lunar landing.
Correct answer is: Apollo 11
Q.9 Which planet is often referred to as Earth's 'twin' because of its similar size and mass?
Mars
Venus
Mercury
Neptune
Explanation - Venus is similar in size and mass to Earth, although its atmosphere and surface conditions are very different.
Correct answer is: Venus
Q.10 Which celestial event occurs when the Moon passes directly between the Sun and Earth?
Lunar eclipse
Solar eclipse
Transit of Venus
Meteor shower
Explanation - During a solar eclipse, the Moon blocks sunlight, casting a shadow on Earth.
Correct answer is: Solar eclipse
Q.11 Which is the largest planet in the solar system?
Saturn
Jupiter
Neptune
Uranus
Explanation - Jupiter is the largest planet with a diameter of about 143,000 km and a mass over 300 times that of Earth.
Correct answer is: Jupiter
Q.12 What type of telescope uses lenses to focus light?
Reflecting telescope
Refracting telescope
Radio telescope
X-ray telescope
Explanation - Refracting telescopes use lenses to bend light and form an image at the focal point.
Correct answer is: Refracting telescope
Q.13 Which of the following is NOT a gas giant planet?
Jupiter
Saturn
Uranus
Mars
Explanation - Mars is a terrestrial planet, while Jupiter, Saturn, Uranus, and Neptune are gas or ice giants.
Correct answer is: Mars
Q.14 Which planet has the longest day in the solar system?
Venus
Mercury
Mars
Jupiter
Explanation - Venus rotates very slowly on its axis, making its day longer than its year.
Correct answer is: Venus
Q.15 What is the main cause of seasons on Earth?
Earth's rotation
Earth's revolution
Earth's axial tilt
Distance from the Sun
Explanation - The tilt of Earth's axis (23.5°) causes variations in sunlight, resulting in seasons.
Correct answer is: Earth's axial tilt
Q.16 Which object in the solar system has the most eccentric orbit?
Earth
Pluto
Mercury
Halley's Comet
Explanation - Halley's Comet has a highly elliptical orbit, taking it from beyond Neptune to close to the Sun.
Correct answer is: Halley's Comet
Q.17 Which type of celestial body is primarily composed of ice and dust and forms a tail when near the Sun?
Asteroid
Comet
Meteoroid
Dwarf planet
Explanation - Comets develop a glowing tail as ice and dust vaporize when they approach the Sun.
Correct answer is: Comet
Q.18 What is the main reason for the retrograde motion of planets as seen from Earth?
Earth's rotation
Earth's orbit relative to other planets
Planetary magnetic fields
Sun's gravity
Explanation - Retrograde motion is an apparent change in planetary motion due to Earth overtaking slower outer planets or being overtaken by faster inner planets.
Correct answer is: Earth's orbit relative to other planets
Q.19 Which planet has the most extensive ring system?
Saturn
Jupiter
Uranus
Neptune
Explanation - Saturn's rings are made of ice and rock, and are the most visible and extensive in the solar system.
Correct answer is: Saturn
Q.20 Which element is most abundant in the Sun?
Helium
Hydrogen
Oxygen
Carbon
Explanation - The Sun is primarily composed of hydrogen (~74%) and helium (~24%), which fuel nuclear fusion.
Correct answer is: Hydrogen
Q.21 What is the approximate age of the universe according to current estimates?
4.5 billion years
13.8 billion years
10 billion years
20 billion years
Explanation - Based on cosmic microwave background radiation and expansion measurements, the universe is about 13.8 billion years old.
Correct answer is: 13.8 billion years
Q.22 Which type of star is at the final stage of its life after shedding its outer layers and leaving a dense core?
Red giant
White dwarf
Neutron star
Supernova
Explanation - White dwarfs are dense stellar remnants formed after low- to medium-mass stars exhaust nuclear fuel and shed outer layers.
Correct answer is: White dwarf
Q.23 Which planet has a retrograde rotation, spinning opposite to most other planets?
Venus
Mercury
Uranus
Mars
Explanation - Venus rotates clockwise (retrograde) while most planets rotate counterclockwise (prograde).
Correct answer is: Venus
Q.24 Which type of telescope is used to detect X-rays from astronomical objects?
Optical telescope
Radio telescope
X-ray telescope
Refracting telescope
Explanation - X-ray telescopes detect high-energy radiation from hot regions in space, like neutron stars and black holes.
Correct answer is: X-ray telescope
Q.25 What is the Kuiper Belt primarily composed of?
Rocky asteroids
Ice and small celestial bodies
Gas giants
Comet tails
Explanation - The Kuiper Belt contains icy objects, dwarf planets, and remnants from the solar system's formation.
Correct answer is: Ice and small celestial bodies