About this quiz
50 questions covering every section of the note.
This Lok Sewa practice set has 50 multiple-choice questions (Subject: Science and Technology · For: Kharidar, Nayab Subba, Section Officer · Level: Easy). Take the quiz above first; after that, use the study list below to revise every question with its correct answer and a short explanation.
Study list: all 50 questions with answers and explanations
What is the name of our galaxy?
- A) Milky Way ✔
- B) Andromeda
- C) Orion
- D) Triangulum
Why: The solar system is part of the Milky Way, a spiral galaxy.
A light-year is a unit of:
- A) Time
- B) Speed
- C) Brightness
- D) Distance ✔
Why: A light-year is the distance light travels in one year, about 9.46 trillion km.
The Sun produces its energy mainly by:
- A) Burning coal
- B) Nuclear fusion of hydrogen into helium ✔
- C) Nuclear fission
- D) Chemical reactions of oxygen
Why: In the Sun's core, hydrogen nuclei fuse to form helium and release energy.
About how long does sunlight take to reach the Earth?
- A) 8 seconds
- B) 1 hour
- C) 8 minutes 20 seconds ✔
- D) 1 day
Why: At about 3 lakh km per second, light covers the 150 million km in about 8 minutes 20 seconds.
Which is the smallest planet of the solar system?
- A) Mars
- B) Pluto
- C) Venus
- D) Mercury ✔
Why: Mercury is the smallest planet and the closest to the Sun. Pluto is now a dwarf planet.
Which planet is the hottest, even though it is not the closest to the Sun?
- A) Venus ✔
- B) Mars
- C) Mercury
- D) Jupiter
Why: Venus is the hottest because its thick carbon dioxide atmosphere traps heat.
Which planet is called the red planet?
- A) Jupiter
- B) Saturn
- C) Mars ✔
- D) Venus
Why: Iron oxide (rust) in its soil makes Mars look red.
The largest planet of the solar system is:
- A) Saturn
- B) Jupiter ✔
- C) Neptune
- D) Uranus
Why: Jupiter is the largest planet and has the Great Red Spot.
In which year was Pluto reclassified as a dwarf planet?
- A) 1996
- B) 2006 ✔
- C) 2001
- D) 2012
Why: The International Astronomical Union reclassified Pluto in 2006.
The asteroid belt lies between the orbits of:
- A) Earth and Mars
- B) Venus and Earth
- C) Jupiter and Saturn
- D) Mars and Jupiter ✔
Why: Most asteroids are found between Mars and Jupiter.
The tilt of the Earth's axis together with its revolution causes:
- A) Seasons ✔
- B) Day and night
- C) Tides
- D) Eclipses
Why: Seasons are caused by the tilted axis (about 23.5 degrees) as the Earth goes round the Sun. Rotation causes day and night.
The gravity on the Moon is about how much of the Earth's gravity?
- A) One half
- B) One quarter
- C) One sixth ✔
- D) Same
Why: The Moon's gravity is about one sixth of the Earth's.
Why do we always see the same face of the Moon?
- A) The Moon does not rotate
- B) The Earth hides the other side
- C) The Moon's rotation and revolution take the same time ✔
- D) The other side has no light
Why: The Moon spins once in the same time it takes to go round the Earth, about 27.3 days.
A solar eclipse can happen only on:
- A) A new moon day ✔
- B) A full moon day
- C) Any day of the month
- D) The first quarter day
Why: In a solar eclipse the Moon is between the Sun and Earth, which happens at new moon (Aunsi).
In a lunar eclipse, which body is in the middle?
- A) The Sun
- B) The Moon
- C) Venus
- D) The Earth ✔
Why: In a lunar eclipse the Earth comes between the Sun and the Moon, and its shadow falls on the Moon.
A solar eclipse in which a bright ring of the Sun is seen around the Moon is called:
- A) Total eclipse
- B) Annular eclipse ✔
- C) Penumbral eclipse
- D) Partial lunar eclipse
Why: In an annular eclipse the Moon looks too small to cover the Sun fully, leaving a ring of light.
Halley's Comet is seen from the Earth about every:
- A) 12 years
- B) 29 years
- C) 165 years
- D) 76 years ✔
Why: Halley's Comet returns about every 76 years; it was last seen in 1986.
Who was the first human to travel into space?
- A) Neil Armstrong
- B) Buzz Aldrin
- C) Yuri Gagarin ✔
- D) Valentina Tereshkova
Why: Yuri Gagarin of the USSR orbited the Earth on 12 April 1961.
The first artificial satellite, launched in 1957, was:
- A) Sputnik 1 ✔
- B) Apollo 11
- C) Explorer 1
- D) Vostok 1
Why: The USSR launched Sputnik 1 on 4 October 1957.
NepaliSat-1, Nepal's first satellite, was launched in:
- A) 2017
- B) 2019 ✔
- C) 2021
- D) 2023
Why: NepaliSat-1 was launched on 17 April 2019 under the BIRDS-3 project, funded by NAST.
Everything that exists — all space, matter and energy — is called the:
- A) Universe ✔
- B) Galaxy
- C) Solar system
- D) Atmosphere
Why: Definition.
The Milky Way is a:
- A) Spiral galaxy ✔
- B) Planet
- C) Comet
- D) Star
Why: Our galaxy is spiral.
The nearest large galaxy to the Milky Way is:
- A) Andromeda ✔
- B) Orion
- C) Pegasus
- D) Ursa Major
Why: Andromeda.
The solar system formed about:
- A) 4.6 billion years ago ✔
- B) 10,000 years ago
- C) 46 million years ago
- D) 460 years ago
Why: About 4.6 billion years.
One Astronomical Unit (AU) is about:
- A) 150 million km ✔
- B) 384,400 km
- C) 9.46 trillion km
- D) 1 lakh km
Why: Earth–Sun distance.
The speed of light is about:
- A) 3 lakh km per second ✔
- B) 3,000 km per second
- C) 30 km per second
- D) 300 km per hour
Why: About 300,000 km/s.
The Sun is a:
- A) Star ✔
- B) Planet
- C) Satellite
- D) Comet
Why: A star.
The Sun holds about what percentage of the solar system's mass?
- A) 99.8% ✔
- B) 50%
- C) 75%
- D) 10%
Why: About 99.8%.
The Sun is made mostly of:
- A) Hydrogen ✔
- B) Oxygen
- C) Iron
- D) Carbon
Why: Hydrogen, then helium.
The visible surface of the Sun is called the:
- A) Photosphere ✔
- B) Corona
- C) Core
- D) Crust
Why: Photosphere.
The Sun's outer layer seen during a total solar eclipse is the:
- A) Corona ✔
- B) Photosphere
- C) Core
- D) Mantle
Why: Corona.
Darker, cooler patches on the Sun are:
- A) Sunspots ✔
- B) Craters
- C) Comets
- D) Rings
Why: Sunspots.
Which planet has no moon and the fastest orbit?
- A) Mercury ✔
- B) Venus
- C) Earth
- D) Mars
Why: Mercury.
Which planet is called the morning and evening star?
- A) Venus ✔
- B) Mars
- C) Jupiter
- D) Saturn
Why: Venus is brightest.
Which planet spins in the opposite direction to most planets?
- A) Venus ✔
- B) Earth
- C) Mars
- D) Jupiter
Why: Retrograde rotation.
Earth is called the:
- A) Blue planet ✔
- B) Red planet
- C) Ringed planet
- D) Dwarf planet
Why: Water covers most of it.
Mars has two small moons named:
- A) Phobos and Deimos ✔
- B) Titan and Rhea
- C) Io and Europa
- D) Triton and Nereid
Why: Mars' moons.
The largest volcano in the solar system, Olympus Mons, is on:
- A) Mars ✔
- B) Venus
- C) Earth
- D) Jupiter
Why: Mars.
The Great Red Spot is a giant storm on:
- A) Jupiter ✔
- B) Mars
- C) Saturn
- D) Neptune
Why: Jupiter.
The largest moon in the solar system is:
- A) Ganymede ✔
- B) Titan
- C) Moon
- D) Phobos
Why: Jupiter's Ganymede.
The least dense planet is:
- A) Saturn ✔
- B) Jupiter
- C) Earth
- D) Mercury
Why: Saturn could float on water.
Titan is the largest moon of:
- A) Saturn ✔
- B) Jupiter
- C) Uranus
- D) Neptune
Why: Saturn.
Which planet rotates on its side?
- A) Uranus ✔
- B) Neptune
- C) Saturn
- D) Mars
Why: Uranus' extreme tilt.
Uranus was discovered by:
- A) William Herschel ✔
- B) Galileo
- C) Newton
- D) Copernicus
Why: 1781.
The farthest planet from the Sun is:
- A) Neptune ✔
- B) Uranus
- C) Saturn
- D) Pluto
Why: Neptune (Pluto is a dwarf planet).
Jupiter and Saturn are called:
- A) Gas giants ✔
- B) Ice giants
- C) Rocky planets
- D) Dwarf planets
Why: Gas giants.
Uranus and Neptune are called:
- A) Ice giants ✔
- B) Gas giants
- C) Terrestrial planets
- D) Asteroids
Why: Ice giants.
The distance between the Earth and the Moon is about:
- A) 384,400 km ✔
- B) 150 million km
- C) 38,440 km
- D) 1 million km
Why: About 384,400 km.
Moonlight is:
- A) Reflected sunlight ✔
- B) The Moon's own light
- C) Starlight
- D) Earthshine only
Why: The Moon has no light of its own.
The Moon takes about how long to go round the Earth?
- A) 27.3 days ✔
- B) 365 days
- C) 24 hours
- D) 7 days
Why: Sidereal month.