McqMate
| 1. |
In LEDs, the longer lead (wire) is always connected to the _______ terminal |
| A. | negative |
| B. | neutral |
| C. | positive |
| D. | Any terminal |
| Answer» C. positive | |
| 2. |
Tap water is a good conductor of electricity while distilled water is not because |
| A. | Tap water contain salts |
| B. | Distilled water do not contain salt |
| C. | Only a) is correct |
| D. | Both a &b is correct |
| Answer» D. Both a &b is correct | |
| 3. |
When electrodes are immersed in water and electricity passed, the bubbles formed on the positive terminal is actually _______ gas. |
| A. | Hydrogen |
| B. | Carbon di oxide |
| C. | Oxygen |
| D. | Nitrogen |
| Answer» C. Oxygen | |
| 4. |
When electrodes are immersed in water and electricity passed, the bubbles formed on the negative terminal is actually _______ gas. |
| A. | Hydrogen |
| B. | Carbon di oxide |
| C. | Oxygen |
| D. | Nitrogen |
| Answer» A. Hydrogen | |
| 5. |
Why do we add little dilute sulphuric acid to copper sulphate solution during electroplating? |
| A. | To increase acidity |
| B. | To increase conductivity |
| C. | So that the colour becomes more prominent |
| D. | To burn copper sulphate |
| Answer» B. To increase conductivity | |
| 6. |
A coating of _________is deposited on iron to protect it from corrosion and formation of rust |
| A. | copper |
| B. | aluminium |
| C. | Zinc |
| D. | silver |
| Answer» C. Zinc | |
| 7. |
Chromium plating is done on many objects such as car parts, bath taps, kitchen gas stove etc. Why? |
| A. | It does not corrode but prevents scratches |
| B. | It looks beautiful |
| C. | It costs less |
| D. | Articles can be sold at higher price |
| Answer» A. It does not corrode but prevents scratches | |
| 8. |
The process of depositing a layer of any desired metal on another material by means of electricity is called ___________. |
| A. | Electric plating |
| B. | Electroplating |
| C. | Electric depositing |
| D. | None of the above |
| Answer» B. Electroplating | |
| 9. |
Some liquids are good conductors of electricity and some are poor conductors. Which one is a poor conductor? |
| A. | Acidic solution |
| B. | Alkaline solution |
| C. | Common Salt solution |
| D. | Distilled water |
| Answer» D. Distilled water | |
| 10. |
Tin cans, used for storing food, are made by electroplating tin onto iron. Why? |
| A. | Tin gives a shiny appearance |
| B. | To make the vessel cheap |
| C. | Tin is less reactive than iron. |
| D. | To make the vessel lighter |
| Answer» C. Tin is less reactive than iron. | |
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