Question 1 :
Small amounts of mineral salts present naturally in water are beneficial for human health. True or false ?

Question 2 :
Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour?

Question 3 :
The passage of an electric current through a conducting liquid causes chemical reactions. The resulting effects are called

Question 6 :
The process of depositing a layer of any desired metal on another material by means of electricity is called ...........................

Question 7 :
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 9 :
Most liquids that conduct electricity are solutions of ......................... , ...................... and .......................

Question 10 :
Most liquids that do not conduct electricity are solutions of acids, bases and salts. TRUE or FALSE?

Question 11 :
The passage of an electric current through a conducting solution causes chemical reactions. As a result -

Question 12 :
<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 13 :
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 16 :
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 17 :
Tin cans used for storing food, are made by electroplating of

Question 18 :
The passage of an electric current through a solution causes ______________ effects.

Question 19 :
<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 21 :
<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 22 :
Most liquids that conduct electricity are solutions of ____________, ______________ and ______________.

Question 23 :
Why the bulb glows when the electric current passes through it?

Question 24 :
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 26 :
<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 27 :
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 28 :
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 29 :
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 30 :
The passage of an electric current through a conducting liquid causes chemical reactions. The resulting effects are called _________.