Question 1 :
Which method is a commonly used chemical method for purifying water?
Question 5 :
Excess of which of the following gas in the air is responsible for this green house effect
Question 7 :
Suspended particulate matter, such as the soot particles emitted by _______ refinery, has contributed towards the yellowing of the marble of Taj Mahal.
Question 8 :
Carbon monoxide is a poisonous gas. It reduces the _____ carrying capacity of the blood
Question 9 :
Combustion of fossil fuels generates a lot of air pollution. Can you suggest any two alternative sources of energy which do not cause any pollution?
Question 10 :
In the following statements, the words in inverted commas are jumbled up. Write them in their correct form. Air contains 78% 'ginroten' and 21% 'gonexy'.
Question 11 :
State True or False.
Pollution is no longer a distant phenomenon. It is affecting the quality of our daily lives.
Question 12 :
Lakhs of trees are planted every year in July. This event is called as-
Question 13 :
This chemical protects our crops and is washed into water bodies from the field-
Question 14 :
State True or False.
A brick kiln emits lot of smoke and other harmful gases causing air pollution.
Question 15 :
The Supreme Court has ordered industries to switch to cleaner fuels like -
Question 16 :
Which part of the Indian population does Ganga river sustains the most?
Question 17 :
Oil refineries, paper factories, textile and sugar mills and chemical factories. How do these industries cause harm to water?
Question 18 :
The excessive quantities of chemicals released in water acts as nutrients for the growth of which organism?
Question 19 :
_________ is produced from incomplete burning of fuels such as petrol and diesel.
Question 21 :
River which is famous in India and sustains most of the northern central and eastern Indian population-
Question 23 :
Name any two water pollutants which are toxic for plants and animals.
Question 25 :
The average temperature of the earth’s atmosphere is gradually increasing. What is it called?
Question 26 :
True or False. Venus has its own moon or satellite of its own.
Question 27 :
Which star is situated in the direction of the earth’s axis and does not appear to move?
Question 28 :
Which planet is earth’s nearest neighbour and is the brightest planet in the night sky?
Question 31 :
Which of the following is NOT a member of the solar system?
Question 35 :
A celestial body that revolves around a planet is known as __________.
Question 36 :
In which part of the sky can you find Venus if it is visible as an evening star?
Question 37 :
There are____ stars in the handle of the ladle and_____ in its bowl
Question 39 :
_______ is another prominent constellation in the northern sky. It is visible during winter in the early part of the night
Question 41 :
The size of the illuminated part of the moon visible from the Earth _____ each day after the new moon day.
Question 42 :
Suppose a new planet is discovered between Uranus and Neptune. Its time period would be ______.
Question 44 :
Venus appears in the eastern sky before sunrise. Sometimes it appears in the western sky just after sunset. Therefore it is often called a _____
Question 45 :
All the stars which make up a constellation are not at the _____distance.
Question 47 :
True or False. Saturn is the least dense among all the planets. Its density is less than that of water.
Question 48 :
At night, when the sky is clear and the moon is not there, sometimes bright streaks of light in the sky can be seen. These are commonly known as_______, although they are not stars. They are called _____
Question 49 :
Does the moon have a large number of steep and high mountains?
Question 50 :
On the fifteenth day the moon is not visible. This day is known as the______
Question 51 :
Heating effect of electric current is the effect of current responsible for the glow of the bulb in an electric circuit.
Question 53 :
One of the most common applications of chemical effect of electric current is __________.
Question 54 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05ef59b460d7261f2d9.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 55 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d054f59b460d7261f2cd.PNG' />
In the image above, Boojho set up this circuit for purification of copper. What will be the nature of plate B?
Question 56 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d058f59b460d7261f2d2.PNG' />
In the above image, which of the following solutions will not make the bulb glow?
Question 57 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d054f59b460d7261f2cd.PNG' />
In the image above, Boojho set up this circuit for purification of copper. What will be the nature of plate B?
Question 58 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d058f59b460d7261f2d1.PNG' />
Current does not flow in the circuit if there is a gap between the two wires. Does it indicate that air is a poor conductor of electricity?
Question 59 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d053f59b460d7261f2cb.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. What would be the effect of increase in the number of turns in the coil wound around the magnetic compass in B?
Question 60 :
Boojho’s uncle has set up an electroplating factory near his village. He should dispose off the waste of the factory
Question 61 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d058f59b460d7261f2d1.PNG' />
Current does not flow in the circuit if there is a gap between the two wires. Does it indicate that air is a poor conductor of electricity?
Question 62 :
Electroplating of ______________ is done on objects like water taps and cycle bell to give them a shiny appearance.
Question 63 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d055f59b460d7261f2ce.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. What does the deflection in magnetic compass indicate?
Question 64 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05cf59b460d7261f2d7.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 65 :
Small amount of a mineral salt present naturally in water makes it a ____________ of electricity.
Question 66 :
Small amount of a mineral salt present naturally in water makes it a ____________ of electricity.
Question 67 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d050f59b460d7261f2c7.PNG' />
Current does not flow in the circuit if there is a gap between the two wires. Does air never conduct electricity?
Question 68 :
Heating effect of electric current is the effect of current responsible for the glow of the bulb in an electric circuit.
Question 69 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d057f59b460d7261f2d0.PNG' />
In the image above, Boojho set up this circuit for purification of copper. What will be the nature of the solution?
Question 70 :
When electric current is passed through a conducting solution, there is a change of colour of the solution. This indicates
Question 71 :
Which of the following metals is used in electroplating to make objects appear shining?
Question 72 :
A coating of zinc is provided to protect iron from corrosion and rust.
Question 73 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05cf59b460d7261f2d6.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 75 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05ef59b460d7261f2d9.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 76 :
Boojho’s uncle has set up an electroplating factory near his village. He should dispose off the waste of the factory
Question 77 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d057f59b460d7261f2d0.PNG' />
In the image above, Boojho set up this circuit for purification of copper. What will be the nature of the solution?
Question 78 :
Which of the following metals is used in electroplating to make objects appear shining?
Question 79 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d059f59b460d7261f2d3.PNG' />
From the above image, we can see that Boojho and Paheli performed experiments taking similar bulbs and cells but two different solutions A and B. They found that the bulb in the setup A glows more brightly as compared to that of the setup B. You would conclude that
Question 81 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d056f59b460d7261f2cf.PNG' />
In the image above, Boojho set up this circuit for purification of copper. What will be the nature of plate A?
Question 83 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d051f59b460d7261f2c9.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. What will be observed if the number of cells are increased in the circuit shown in B?
Question 84 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d050f59b460d7261f2c7.PNG' />
Current does not flow in the circuit if there is a gap between the two wires. Does air never conduct electricity?
Question 85 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d051f59b460d7261f2c9.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. What will be observed if the number of cells are increased in the circuit shown in B?
Question 86 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05cf59b460d7261f2d7.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 87 :
When electric current is passed through a conducting solution, there is a change of colour of the solution. This indicates
Question 88 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d050f59b460d7261f2c8.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. Why did the bulb not glow in A?
Question 90 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05ff59b460d7261f2da.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 91 :
Electroplating of ______________ is done on objects like water taps and cycle bell to give them a shiny appearance.
Question 93 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d058f59b460d7261f2d2.PNG' />
In the above image, which of the following solutions will not make the bulb glow?
Question 94 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05cf59b460d7261f2d6.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 96 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d055f59b460d7261f2ce.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. What does the deflection in magnetic compass indicate?
Question 97 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d053f59b460d7261f2cb.PNG' />
In the above image, observing that the bulb does not glow in the circuit shown in A, Boojho changed the circuit as shown in B. He observed deflection in the magnetic compass. What would be the effect of increase in the number of turns in the coil wound around the magnetic compass in B?
Question 98 :
A coating of zinc is provided to protect iron from corrosion and rust.
Question 100 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d05ff59b460d7261f2da.PNG' />
In the image above, will the bulb glow. Write ‘Yes’ or ‘No’
Question 101 :
State True or False:
There are nine planets in the solar system.
Question 102 :
Which of the following is NOT a planet of the Sun ?
Question 103 :
Which ofthe following is NOT a member of the solar system ?
Question 104 :
State True or False:
Constellation Oriun can be seen only with a telescope
Question 106 :
Which is the the largest planet of the solar system ?
Question 108 :
A group of stars that appear to form a pattern in the sky is known as a
Question 110 :
A group of stars forming some kind of recognisable figures or patterns are known as
Question 111 :
Name the objects other than planets which are members of the solar system.
Question 112 :
A celestial body that revolves around a planet is known as_
Question 116 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0fdf59b460d7261f3a3.jpg' />
Boojho made the above sketch of the solar system. Is the sketch correct ? Yes/No
Question 117 :
State True or False:
Mercury is the smallest planet of the solar system.
Question 120 :
The radius of Jupiter is 11 times the radius of the Earth. How many Earths can Jupiter accommodate?
Question 122 :
In which part of the sky can you find Venus if it is visible as an evening star?
Question 125 :
State True or False:
Uranus is the farthest planet in the solar system.
Question 127 :
If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the negative terminal of the battery. TRUE or FALSE?
Question 128 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0bff59b460d7261f34f.PNG' />
In the above figure, an activity is shown. Collect a few small plastic or rubber caps of discarded bottles and clean them. Pour one teaspoon of lemon juice or vinegar in one cap. Bring your tester over this cap and let the ends of the tester dip into lemon juice or vinegar as shown in figure. Take care that the ends are not more than 1 cm apart but at the same time do not touch each other. Does the bulb of the tester glow?
Question 132 :
The passage of an electric current through a conducting liquid causes chemical reactions. The resulting effects are called _________.
Question 134 :
Most liquids that conduct electricity are solutions of ____________, ______________ and ______________.
Question 136 :
Take about two teaspoonfuls of distilled water in a clean and dry plastic or rubber cap of a bottle. Use the tester to test whether distilled water conducts electricity or not.
Question 138 :
When salt is dissolved in distilled water, we obtain salt solution. This is a insulator of electricity. TRUE or FALSE?
Question 139 :
The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating. Is the definition correct ?
Question 140 :
While preparing a list of objects around you that are electroplated, you may include -
Question 143 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0bdf59b460d7261f34d.PNG' />
In the above figure, activity is shown. Take out carbon rods carefully from two discarded cells. Clean their metal caps with sand paper. Wrap copper wires around the metal caps of the carbon rods and join them to a battery Pour a cupful of water in a glass/plastic bowl. Add a teaspoonful of salt or a few drops of lemon juice to water to make it more conducting. Now immerse the electrodes in this solution. Make sure that the metal caps of the carbon rods are outside the water. Wait for 3-4 minutes. Observe the electrodes carefully. Do you notice any gas bubbles near the electrodes?
Question 144 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61cc1ad678c526e972caf080.PNG' />
Name three liquids, which when tested in the manner shown in the above figure, may cause the magnetic needle to deflect.
Question 145 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0c4f59b460d7261f356.PNG' />
In the above figure, name the liquid(s), which when tested in the manner, may cause the magnetic needle to deflect.
Question 146 :
Why the bulb glows when the electric current passes through it?
Question 148 :
A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transferred to the thin copper plate. Which electrode should be attached to the positive terminal of battery?
Question 149 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0bff59b460d7261f350.PNG' />
In the above figure, an activity is shown. Collect a few small plastic or rubber caps of discarded bottles and clean them. Pour one teaspoon of lemon juice or vinegar in one cap. Bring your tester over this cap and let the ends of the tester dip into lemon juice or vinegar as shown in figure. Take care that the ends are not more than 1 cm apart but at the same time do not touch each other. How would you classify lemon juice or vinegar - a good conductor or a poor conductor?
Question 150 :
When an electric current flows through a conducting solution, does it produce an effect on the solution?
Question 152 :
Tin cans used for storing food, are made by electroplating of
Question 153 :
Take about two teaspoonfuls of distilled water in a clean and dry plastic or rubber cap of a bottle. Does distilled water conduct electricity?
Question 156 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0c3f59b460d7261f355.PNG' />
In the above figure, an activity is shown. We will need copper sulphate and two copper plates of size around 10 cm × 4 cm. Take 250 mL of distilled water in a clean and dry beaker. Dissolve two teaspoonfuls of copper sulphate in it. Add a few drops of dilute sulphuric acid to copper sulphate solution to make it more conducting. Clean copper plates with sand paper. Now rinse them with water and dry them. Connect the copper plates to the terminals of a battery and immerse them in copper sulphate solution figure. Allow the current to pass for about 15 minutes. Now remove the electrodes from the solution and look at them carefully. What colour is the coating?
Question 157 :
There are two wires (called leads) attached to an LED. One lead is slightly longer than the other. TRUE or FALSE?
Question 158 :
A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of the battery?
Question 159 :
The process of depositing a layer of any desired metal on another material by means of electricity is called ...........................
Question 160 :
Iron is used in bridges and automobiles to provide strength. However, iron tends to corrode and rust. So, a coating of ____ is deposited on iron to protect it from corrosion and formation of rust.
Question 161 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0c0f59b460d7261f351.PNG' />
In the above figure, an activity is shown. We will need copper sulphate and two copper plates of size around 10 cm × 4 cm. Take 250 mL of distilled water in a clean and dry beaker. Dissolve two teaspoonfuls of copper sulphate in it. Add a few drops of dilute sulphuric acid to copper sulphate solution to make it more conducting. Clean copper plates with sand paper. Now rinse them with water and dry them. Connect the copper plates to the terminals of a battery and immerse them in copper sulphate solution figure. Allow the current to pass for about 15 minutes. Now remove the electrodes from the solution and look at them carefully. Do you find a coating over it?
Question 163 :
LED's have longer lifetime than light bulbs and fluorescent tubes. TRUE or FALSE?
Question 164 :
Most liquids that do not conduct electricity are solutions of acids, bases and salts. TRUE or FALSE?
Question 165 :
A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. You would conclude that
Question 168 : <img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0bef59b460d7261f34e.PNG' />
In the above figure, an activity is shown. Collect a few small plastic or rubber caps of discarded bottles and clean them. Pour one teaspoon of lemon juice or vinegar in one cap. Bring your tester over this cap and let the ends of the tester dip into lemon juice or vinegar as shown in figure. Take care that the ends are not more than 1 cm apart but at the same time do not touch each other. Does lemon juice or vinegar conduct electricity?
Question 169 :
The passage of an electric current through a solution causes ..................... effects.
Question 173 :
Small amounts of mineral salts present naturally in water are beneficial for human health. True or false ?
Question 174 :
The passage of an electric current through a solution causes ______________ effects.
Question 175 :
Most liquids that conduct electricity are solutions of ......................... , ...................... and .......................
