Question 11 Mark
The headlights of a car have reflectors behind the bulb. What is the function of reflectors?
Answer
View full question & answer→The reflector helps in reflecting the light into a focussed area.
Questions
[1 Marks Each] QUE - ANS
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83 questions · self-marked practice — reveal the answer and mark yourself.
Question 21 Mark
In any electric circuit, when the switch is on and the current flows through it why do the wire, switches, bulb or devices become hot?
Answer
View full question & answer→This is because electric energy changes into heat energy.
Question 31 Mark
Give one activity to prove that air is an insulator.
Answer
View full question & answer→Take an electric circuit, keep the terminals unconnected in the air. The bulb do not glow, as air is an insulator and does not allow the current to flow through it.
Question 41 Mark
Name the scientist who invented electric cell and the scientist who invented electric bulb.
Answer
View full question & answer→Electric cell: Alessandro Volta.
Electric bulb: Thomas Alva Edison.
Electric bulb: Thomas Alva Edison.
Question 51 Mark
Identify conductors and insulators from the following:Eraser, paper, matchstick, copper wire, pencil lead, polythene
Answer
View full question & answer→Conductors: Copper wire, pencil lead.
Insulator. Eraser, paper, matchstick, polythene.
Insulator. Eraser, paper, matchstick, polythene.
Question 61 Mark
Define conductors and insulators. Give one example of each.
Answer
View full question & answer→A conductor is that which easily allows the passage of current through it. Example: Aluminium or any metal.
An insulator is that which does not allow the passage of current through it. Example: Rubber.
An insulator is that which does not allow the passage of current through it. Example: Rubber.
Question 71 Mark
Mention two advantages of a dry cell.
Answer
View full question & answer→$1.$ It converts chemical energy into electrical energy.
$2.$ It is light and small in size.
$2.$ It is light and small in size.
Question 81 Mark
What is the name of thin wire in the electric bulb?
Answer
View full question & answer→Filament.
Question 91 Mark
Write one use of insulators.
Answer
View full question & answer→Insulators are used in making switchboard, handles of testers, screw drivers.
Question 101 Mark
What is open circuit?
Answer
View full question & answer→An electric circuit in which electrical contact at any point is broken is called open circuit.
Question 111 Mark
What is solar cell?
Answer
View full question & answer→ A device which converts solar energy into electrical energy.
Question 121 Mark
What is dry cell?
Answer
View full question & answer→It is a device which converts chemical energy into electrical energy.
Question 131 Mark
Name the $-ve$ terminal of a dry cell.
Answer
View full question & answer→Zinc metal plate.
Question 141 Mark
Name the $+ve$ terminal of dry cell.
Answer
View full question & answer→Carbon rod with a metal cap on it.
Question 151 Mark
What is the direction of flow of current in a dry cell?
Answer
View full question & answer→The current flows in closed circuit from $+ve$ to $-ve$ terminal of cell.
Question 161 Mark
Using the“conduction tester” on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.
Answer
View full question & answer→Yes, if the object is good conductor of electricity then current will pass through conduction tester and the bulb will glow. Hence the object will be a conductor of electricity.
Question 171 Mark
Would the bulb glow in the circuit shown in Fig. $12.11.$
Answer
View full question & answer→Yes, the electric circuit is closed so the bulb will glow.
Question 181 Mark
Would the bulb glow after completing the circuit shown in Fig. $12.9$ if instead of safety pin we use an eraser?
Answer
View full question & answer→No, since eraser is an insulator so it does not allow the current to pass. Hence the bulb will not glow.
Question 191 Mark
What is the purpose of using an electric switch? Name some electrical gadgets that have switches built into them.
Answer
View full question & answer→Electric switch is used to make electric circuit open or closed for a particular appliance and hence with the help of a switch we can use an appliance according
Question 201 Mark
Explain why the bulb would not glow in the arrangement shown in fig
Answer
View full question & answer→The bulb would not glow in the arrangement shown in figure because the one end of tester/screw driver is made up of plastic which does not allow the electric current to flow through it.
Question 211 Mark
Think about the night sky and write a poem or a story on it.
Answer
View full question & answer→Do it yourself.
Question 221 Mark
During a clear night, try to observe the Big Dipper $3-4$ times at , an interval of $2$ to $3$ hours. Also try to locate the Pole Star each time. Does the Big Dipper appear to move? Draw a rough sketch to illustrate this, mentioning the time in each case.
Answer
View full question & answer→The Big Dipper appears to move around the Pole Star due to the rotation of the Earth. Over a few hours, its position changes, making it seem as if it is rotating around the Pole Star.
Question 231 Mark
You can see stars fading away at dawn and appearing f at dusk. During the day we do not see the stars. Explain why?
Answer
View full question & answer→During the day, the Sun’s bright light outshines the stars, making them invisible to our eyes. The atmosphere scatters the sunlight, creating the blue sky and masking the faint light of the stars.
Question 241 Mark
An artist’s representation of the Solar System is given in Figure. Is the order of the planets correct? If not, write the correct order in the boxes in the figure.
Answer
View full question & answer→The order of the planets in the figure is not correct. The correct order from the Sun is: Mercuiy, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
Question 251 Mark
Which is the brighter star, the Pole Star or Sirius?
Answer
View full question & answer→Sirius
Question 261 Mark
How many types of electric circuit are there? Define them.
Answer
View full question & answer→There are two types of electric circuit:
$(a)$ Open electric circuit
$(b)$ Closed electric circuit
$(a)$Open electric circuit: The circuit in which electrical contact at any point is broken is called open electric circuit.
$(b)$Closed electric circuit: The circuit in which electric current flows from one terminal of a cell or battery to the other is called a closed circuit.
$(a)$ Open electric circuit
$(b)$ Closed electric circuit
$(a)$Open electric circuit: The circuit in which electrical contact at any point is broken is called open electric circuit.
$(b)$Closed electric circuit: The circuit in which electric current flows from one terminal of a cell or battery to the other is called a closed circuit.
Question 271 Mark
What is electric circuit?
Answer
View full question & answer→The diagram that shows the path of electric current is called electric circuit.
Question 281 Mark
What Is the name of Chandrayaan $3$ mission’s lander and the rover?
Answer
View full question & answer→Chandrayaan $3$ mission’s lander is named Vikram and the rover Pragyan.
Question 291 Mark
What Is the name of the successful mission by Indta which demonstrated end-toend capability in safe landing and roving on the lunar surface?
Answer
View full question & answer→Chandrayaan-$3$ demonstrated end-to-end capability in safe landing and roving on the lunar surface.
Question 301 Mark
What is the scientific study of universe called?
Answer
View full question & answer→The scientific study of universe is called Astronomy.
Question 311 Mark
Define Universe.
Answer
View full question & answer→The Universe is a large space consisting of celestial bodies like the stars, planets, galaxy, dust and gases.
Question 321 Mark
Why is our galaxy calledMilky Way?
Answer
View full question & answer→Our galaxy is called the Milky Way because it appears as a milky hand of light in the sky when we see it in a really dark area.
Question 331 Mark
What is the other name of Milky Way Galaxy?
Answer
View full question & answer→Milky Way galaxy is often known as Akash Ganga.
Question 341 Mark
What is the shape of the Milky Way Galaxy?
Answer
View full question & answer→Our Milky Way Galaxy is a spiral galaxy having a whitish broadand. It looks like a spinning pinwheel when viewed from top or bottom.
Question 351 Mark
What is a galaxy?
Answer
View full question & answer→A galaxy is a huge system of billions of stars, and clouds of dust and gases.
Question 361 Mark
Why is Venus called the Twin Planet?
Answer
View full question & answer→Venus is considered as ‘Earth’s-twin’ because its size and shape are very much similar to that of the earth.
Question 371 Mark
What is the other name of outer planets and name them?
Answer
View full question & answer→Outer planets are also called Jovian planets. They are- Jupiter, Saturn, Uranus and Neptune.
Question 381 Mark
What is the other name of inner planets and name them?
Answer
View full question & answer→Inner planets are also called Terrestrial planets, They are – Mercury, Venus, Earth and Mars.
Question 391 Mark
What are artificial satellites used for?
Answer
View full question & answer→Artificial satellites are used for weather forecasting, long distance communication and remote sensing.
Question 401 Mark
Why is Jupiter called the Stormy Planet?
Answer
View full question & answer→Jupiter revolves around itself with a great speed; hence Jupiter is called the Stormy planet.
Question 411 Mark
When is ‘National Space Day’ celebrated in India?
Answer
View full question & answer→‘National Space Day’ is celebrated on August 23rd every year.
Question 421 Mark
What is a Dwarf Planet?
Answer
View full question & answer→A small sized celestial body that revolves independently around the sun is called the dwarf planet.
Question 431 Mark
Which planet is called “morning or evening star and why?
Answer
View full question & answer→Venus is usually seen shining brightly at dawn and dusk, and is commonly called the Morning Star or the Evening Star, even though it is not a star,
Question 441 Mark
Which planet is known as the “Red Planet” and why?
Answer
View full question & answer→Mars is called the Red Planet because it appears red. This is because the soil on Mars is reddish in colour.
Question 451 Mark
Why is Moon not considered a planet?
Answer
View full question & answer→The Moon isn’t a planet because it orbits the Earth.
Question 461 Mark
What do planets in the solar system orbit around?
Answer
View full question & answer→The planets orbit around the Sun.
Question 471 Mark
How many planets in the solar system are made of gas? Name them.
Answer
View full question & answer→Four planets are made out of gas and they are also referred to as gas giants. They are Jupiter, Saturn, Uranus, and Neptune.
Question 481 Mark
Which planet is the hottest in our solar system?
Answer
View full question & answer→Venus is the hottest planet in our solar system.
Question 491 Mark
Which galaxy is our solar system part of?
Answer
View full question & answer→Our solar system is in the Milky Way Galaxy.
Question 501 Mark
What is revolution?
Answer
View full question & answer→The motion of the earth around the sun in its orbit is known as revolution.
Question 511 Mark
Why is the Earth called a blue planet?
Answer
View full question & answer→From the outer space, the earth appears blue because its three- fourths surface is covered by water. It is, therefore, called a blue planet.
Question 521 Mark
What is meant by the ‘Solar System’?
Answer
View full question & answer→The sun, eight planets, satellites and some other celestial bodies known as asteroids and meteoroids form the solar system.
Question 531 Mark
Do stars emit light only during night?
Answer
View full question & answer→No, they emit light all the time.
Question 541 Mark
How do astronomers use constellations?
Answer
View full question & answer→Astronomers use constellations as a way to identify and- locate stars and other celestial objects in the night sky, aiding navigation and observation.
Question 551 Mark
What are the other names of Pole Star?
Answer
View full question & answer→Polaris/Dhruv Tara/ North Star/ Guiding Star are the other names of Pole Star.
Question 561 Mark
Identify the following constellations:
Answer
View full question & answer→$(a)$ Ursa Major/Big Dipper
$(b)$ Ursa Minor/Little Dipper
$(b)$ Ursa Minor/Little Dipper
Question 571 Mark
What causes stars to rise and set?
Answer
View full question & answer→This occurs due to Earth’s rotation which is spinning around its own axis.
Question 581 Mark
What is Universe?
Answer
View full question & answer→The Universe is a large space consisting of celestial bodies like the stars, planets, galaxy, dust and gases.
Question 591 Mark
What is the distance between the Sun and the Earth?
Answer
View full question & answer→The distance of the Sun from the Earth is about $150$ million km.
Question 601 Mark
Which are the four main stars we know?
Answer
View full question & answer→Sun, Proxima Centauri, Alpha Centauri and Sirius.
Question 611 Mark
Which device is used to observe faint stars which are not visible to the naked eye?
Answer
View full question & answer→Powerful telescopes are used to observe faint stars that are not visible to the naked eye.
Question 621 Mark
A star is ten light years away from the earth. Suppose it brightens up suddenly today. After how much time shall we see this change?
Answer
View full question & answer→We will see the change seen after $10$ years
Question 631 Mark
Which is the brightest star in the night sky?
Answer
View full question & answer→Sirius is the brightest star in the night sky.
Question 641 Mark
Which star is nearest to us after the Sun?
Answer
View full question & answer→Proxima tentauri is the star nearest to us after the Sun.
Question 651 Mark
Which is the closest star to the Earth?
Answer
View full question & answer→The Sun is the closest star to the Earth.
Question 661 Mark
What is a shooting star?
Answer
View full question & answer→A shooting star is actually a meteor burning up in Earth’s atmosphere, causing a streak of light in the sky.
Question 671 Mark
What is a constellation?
Answer
View full question & answer→A constellation is a group of stars that form a recognizable pattern in the sky.
Question 681 Mark
Solve the riddles: I’m the planet that everyone calls “Red,” But really my soil is rust-colored instead. Look up and you may spot me in the sky, I’m the orange- colored dot, way up high. Which planet am I?
Answer
View full question & answer→Mars
Question 691 Mark
Solve the riddles: Eight of us travel around the sun, you live on one. What am I?
Answer
View full question & answer→Planet
Question 701 Mark
Farthest planet from Sun.
Answer
View full question & answer→Neptune
Question 711 Mark
Planet having rings.
Answer
View full question & answer→Saturn
Question 721 Mark
Largest planet in our Solar System.
Answer
View full question & answer→Jupiter
Question 731 Mark
Second; farthest planet from Sun.
Answer
View full question & answer→Uranus
Question 741 Mark
Nearest planet to Sun.
Answer
View full question & answer→Mercury
Question 751 Mark
A dwarf planet.
Answer
View full question & answer→Pluto
Question 761 Mark
Winds blow with extremely high speed on
Answer
View full question & answer→Neptune
Question 771 Mark
Stormy planet
Answer
View full question & answer→Jupiter
Question 781 Mark
A celestial body that carries a tail along.
Answer
View full question & answer→Comet
Question 791 Mark
Planet with the largest number of satellites.
Answer
View full question & answer→Saturn
Question 801 Mark
The galaxy which is our neighbour.
Answer
View full question & answer→Andromeda
Question 811 Mark
Evening Star.
Answer
View full question & answer→Venus
Question 821 Mark
Two planets between which Saturn lies.
Answer
View full question & answer→Jupiter and Uranus
Question 831 Mark
Bltie planet of the solar system.
Answer
View full question & answer→Earth