18 Questions
Why are we cautioned against touching an electrical appliance with wet hands?
Water is a good conductor of electricity, increasing the risk of electric shock.
What did we learn about materials in Class VI that allow electric current to pass through them?
They are good conductors of electricity.
Why should one only use electric cells for activities involving electricity?
Using other sources like mains can be dangerous during experiments.
Why do materials such as rubber, plastic, and wood not conduct electricity?
They lack free electrons for current flow.
In the context of conducting electricity, why is it important to check if the tester is working before use?
To verify that the tester lights up when current flows through it.
Why is using a battery instead of a cell recommended for testing liquids' conductivity?
A battery provides a higher voltage for better conductivity testing.
Why is it preferable to classify materials as good conductors and poor conductors instead of as conductors and insulators?
To emphasize the variations in conductivity among different materials
Why is salt solution considered a conductor of electricity?
Because it contains mineral salts dissolved in it
What type of water is a poor conductor of electricity?
Distilled water free of salts
Which types of liquids are known to conduct electricity?
Solutions of acids, bases, and salts
What does the table in the text indicate about the liquids tested?
Some liquids are good conductors and some are poor conductors.
Why should electrical appliances never be handled with wet hands or on a wet floor?
To avoid getting electrocuted due to water's conductivity
In the activity described, why is there an air gap between the free ends of the tester?
To test if air is a conductor of electricity.
What common substance, when dissolved in distilled water, can also make it a good conductor of electricity?
Vinegar
Based on Paheli's knowledge, why is she surprised about the conductivity of air during lightning?
Because she knows air is typically a poor conductor.
What does Boojho wonder about in relation to materials classified as poor conductors?
Whether they can conduct under certain conditions.
After testing distilled water, what do the students find about its conductivity?
Distilled water is a poor conductor of electricity.
What conclusion can be drawn after testing distilled water with added common salt?
Distilled water becomes a good conductor with salt added.
Study Notes
Electricity and Conductivity
- We are cautioned against touching electrical appliances with wet hands because water is a good conductor of electricity, and it can facilitate the flow of electric current through our bodies.
- Materials that allow electric current to pass through them are called conductors, and we learned about them in Class VI.
- Electric cells should only be used for activities involving electricity because they are designed to provide a steady flow of electricity.
- Materials like rubber, plastic, and wood do not conduct electricity because they do not have free electrons that can move freely to conduct electric current.
- It's essential to check if the tester is working before use to ensure accurate results and avoid false conclusions.
- Using a battery instead of a cell is recommended for testing liquids' conductivity because batteries provide a more stable and consistent flow of electricity.
- Materials are preferably classified as good conductors and poor conductors instead of conductors and insulators because it allows for a more nuanced understanding of their properties.
- Salt solution is considered a conductor of electricity because it facilitates the flow of electric current due to the presence of free ions.
- Distilled water is a poor conductor of electricity because it does not contain ions or electrolytes that can facilitate the flow of electric current.
- Liquids like salt solution, lemon juice, and tap water are known to conduct electricity, as indicated by the table in the text.
- Electrical appliances should never be handled with wet hands or on a wet floor because water can conduct electricity and cause accidents.
- The air gap between the free ends of the tester is essential to prevent the flow of electricity and ensure accurate results.
- Common salt, when dissolved in distilled water, can make it a good conductor of electricity.
- Paheli is surprised about the conductivity of air during lightning because air is typically considered a poor conductor, but during lightning, the air is ionized, making it a good conductor.
- Boojho wonders why materials classified as poor conductors do not conduct electricity.
- After testing distilled water, the students find that it is a poor conductor of electricity.
- The conclusion drawn after testing distilled water with added common salt is that it becomes a good conductor of electricity.
Explore the conduction of electricity in liquids through a simple science experiment. Test the conductivity of tap water and distilled water to determine whether they are good or poor conductors of electricity.
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