Question 1 : <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 2 : <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 3 : <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 4 :
Small amount of a mineral salt present naturally in water makes it a ____________ of electricity.
Question 5 :
One of the most common applications of chemical effect of electric current is __________.
Question 6 : <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 7 : <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 8 : <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 9 : <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 10 : <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 11 :
Boojho’s uncle has set up an electroplating factory near his village. He should dispose off the waste of the factory
Question 12 :
Heating effect of electric current is the effect of current responsible for the glow of the bulb in an electric circuit.
Question 14 :
Heating effect of electric current is the effect of current responsible for the glow of the bulb in an electric circuit.
Question 15 : <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 16 : <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 17 :
A coating of zinc is provided to protect iron from corrosion and rust.
Question 18 :
A coating of zinc is provided to protect iron from corrosion and rust.
Question 19 : <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 20 : <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 27 :
State true or false. A whistle has a high frequency and therefore, produces a sound of low pitch
Question 28 :
Lightning can be seen the moment it occurs. Paheli observes lightning in her area. She hears the sound 5 s after she observed lightning. How far is she from the place where lightning occurs? (speed of sound = 330 m/s).
Question 30 :
When we hear a sound, does any part of our body vibrate?
Question 31 :
We have a stringed musical instrument. The string is plucked in the middle first with a force of greater magnitude and then with a force of smaller magnitude. In which case would the instrument produce a louder sound?
Question 32 :
Boojho saw a cracker burst at night at a distance from his house. He heard the sound of the cracker a little later after seeing the cracker burst. Give reason for the delay in hearing the sound.
Question 33 :
A pendulum oscillates 40 times in 4 seconds. Find its frequency.
Question 38 :
Fill in the blank: Time taken by an object to complete one oscillation is called ______.
Question 39 :
If the amplitude of vibration is large, sound is feeble. State true or false.
Question 40 :
State True or False: The number of oscillations per second of a vibrating object is called its time period.
Question 41 :
A sudden shaking or trembling of the earth which lasts for a very short time is known as
Question 42 :
Which process is called when negative and positive charges meet, producing streaks of bright light and sound in clouds?
Question 43 :
The earthquake measuring ______ or more on Richter scale can cause severe damage to life and property.
Question 44 :
Give the precautions that you will take to protect yourself if earthquake strikes when you are inside the house.
Question 45 :
Lightning conductor cannot protect a building from lightning. State TRUE or FALSE.
Question 46 :
State true or false. The process of electric discharge cannot occur between clouds and the earth.
Question 47 :
What precautions would you take if lightning occurs while you are outside the house?
Question 48 :
The strips carrying similar charges _________ each other and they become wide open.
Question 49 :
The power of an earthquake is expressed in terms of a magnitude on a scale called
Question 51 :
Plastic straws A and B are rubbed with dry cotton cloth. What will happen if they are brought near each other?
Question 52 :
An earthquake measures 3 on the richer scale. Would it be recorded by a seismograph?
Question 54 :
_________ and _________ charges meet, producing streaks of bright light and sound.
Question 57 :
State true or false. The plates of the outermost layer of the earth are always in continuous motion.
Question 58 :
What precautions should be taken if you are Inside the house during a thunderstorm?
Question 59 :
It is a convention to call the charge acquired by a glass rod when it is rubbed with silk as positive. The other kind of charge is said to be negative. Is it TRUE OR FALSE?
Question 60 :
What precautions should be taken if one is outside in a forest where no shelter is available and you are in an open field during a thunderstorm?
