CBSE Chapter 11 Chemical Effects Of Electric Current Long Answer Type Questions
Question 1. Prove that lemon juice and vinegar are good conductors of electricity.
Answer: Take a few plastic or rubber cap bottles. Put a teaspoon of lemon juice or vinegar in one cap.
Read And Learn More CBSE Class 8 Science Long Answer Questions
Now, bring the tester over the cap and let the ends ofthe tester dip into lemon juice or vinegar. So, we can see that, bulb starts to glow. It indicates that lemon juice and vinegar are good conductors of electricity.
” Cbse Class 8 Science Chapter 11 Laqs “
Question 2. You are provided with n magnetic compasses, an empty matchbox, a battery of two cells and connecting wires. Using these objects, how will you make a tester for testing an electric circuit? Draw the necessary circuit diagram and explain.
” Chemical Effects Of Electric Current Class 8 “
Answer: Take the tray from the inside of a discarded matchbox. Wrap an electric wire a few times around the tray. Place a small compass needle inside it. Now connect one free end of the wire to one terminal of a battery.
Leave the other end free. Take another piece of wire and connect it to the other terminal of the battery. Join the free ends of two wires momentarily.
The compass needle should show deflection. Your tester with two free ends of the wire is ready.
” Conductivity Of Lemon Juice And Vinegar “
Question 3. Observing that the bulb does not glow in the circuit. Boojho changed the circuit. He observed deflection in the magnetic compass.
” Magnetic Compass Deflection Experiment “
- What does the deflection in the magnetic compass indicate?
- Why did the bulb not glow in?
- What would be the effect of an increase in the number of turns in the coil wound around the magnetic compass?
Answer:
- The deflection in the magnetic compass shows that the current is flowing in the circuit.
- The bulb did not glow, it may be because of the current passing through the circuit could be weak. Also, it may happen because ofother reasons like due to bulb fused or the connections may be loose.
- An increase in the number of turns in the coil wound Around the magnetic compass would increase the magnetic field around the magnetic compass which will result in the increase in the deflection in the magnetic compass.
” Lemon Juice As A Conductor Of Electricity “
Question 4. One day Ram was performing an experiment. He was trying to design an electric circuit In which he Included tester, bulb and a battery.
He had so much eagerness regarding this experiment that, in much haste, he forgot to take the connecting wires of aluminium.
He took the wires without any coating of PVC on them, so it could be dangerous for him. Any how, he managed to design an electric circuit but the moment, he switched ON the circuit, a spark was produced and bulb got fused with a small sound.
He was about to touch those wires and heated bulb with his bare hands, at the same time, his teacher suggested him to perform the experiment by taking precautions. Explain what could have happened if Ram had touched the electric bulb with his bare hands.
Mention why he should use the aluminium wires in his experiment? State the values shown by Ram’s teacher here.
” Electroplating Process Class 8 “
Answer: If Ram touched the heated electric bulb, then his hands could get a severe burn, and he would not be able to experiment again with the same desire.
He uses the aluminium wires in his experiment because aluminium is a good conductor of electricity.
Ram’s teacher has a great concern towards Ram, so that he can perform the experiment carefully and can get to its fruitful conclusion.
