Q 1 – Polythene is (1 Marks)
(a) a conductor
(b) an insulator
(c) both (a) and (b)
(d) none of these
Q 2 – Flow of electron is called (1 Marks)
(a) electrolyte
(b) electroplating
(c) electrodes
(d) electric current
Q 3 – Which of the following is a bad conductor of electricity? (1 Marks)
(a) Distilled water
(b) Silver nitrate
(c) Sulphuric acid
(d) Copper sulphate
Q 4 – Which of the following does not conduct electricity? (1 Marks)
(a) Sugar solution
(b) Vinegar solution
(c) Lemon juice solution
(d) Caustic soda solution
Q 5 – Pure or distilled water is a(1 Marks)
(a) poor conductor
(b) good conductor
(c) both (a) and (b)
(d) none of these
Q 6 – Electroplating is based on(1 Marks)
(a) heating effect of electricity
(b) chemical effect of electricity
(c) physical effect of electricity
(d) magnetic effect of electricity
Q 7 – Copper is (1 Marks)
(a) a good conductor
(b) an insulator
(c) both (a) and (b)
(d) none of these
Q 8 – An electrolyte is (1 Marks)
(a) a metal
(b) a liquid that conducts current
(c) a non-metal
(d) none of these
Q 9 – In LEDs, the longer lead (wire) is always connected to the _______ terminal (1 Marks)
(a) negative
(b) neutral
(c) positive
(d) Any terminal
Q 10 – Tap water is a good conductor of electricity while distilled water is not because (1 Marks)
(a) Tap water contains salts
(b) Distilled water does not contain salt
(c) Only (a) is correct
(d) Both (a) & (b) is correct
Q 11 – When electrodes are immersed in water and electricity passed, the bubbles formed on the positive terminal is actually _______ gas. (1 Marks)
(a) Hydrogen
(b) Carbon dioxide
(c) Oxygen
(d) Nitrogen
Q 12 – Why do we add little dilute sulphuric acid to copper sulphate solution during electroplating? (1 Marks)
(a) To increase acidity
(b) To increase conductivity
(c) So that the colour becomes more prominent
(d) To burn copper sulphate
Q 13 – A coating of _________is deposited on iron to protect it from corrosion and formation of rust (1 Marks)
(a) copper
(b) aluminium
(c) Zinc
(d) silver
Q 14 – Chromium plating is done on many objects such as car parts, bath taps, kitchen gas stove etc. Why? (1 Marks)
(a) It does not corrode but prevents scratches
(b) It looks beautiful
(c) It costs less
(d) Articles can be sold at a higher price
Q 15 – Kerosene is: (1 Marks)
(a) electrolyte
(b) non-electrolyte
(c) electrode
(d) none of these
Q 16 – During electroplating in CuSO4, (Copper sulphate) solution …………………. will get deposit on the electrode at negative terminal. (1 Marks)
(a) Copper from the positive electrode
(b) Sulphur
(c) Copper from CuSO4 , solution
(d) None of these
Q 17 – Fill in the blanks: (4 Marks)
- A cation has ___________ charge.
- The passage of an electric current through a conducting solution causes ___________.
- An electric lamp glows due to ___________ effect of electric current.
- __________does not corrode easily.
Q 18 – How is the conductivity of liquids tested? (1 Marks)
Q 19 – An LED is more efficient device than a bulb. Why? (2 Marks)
Q 20 – Define good conductors and poor conductors or insulators. (2 Marks)
Q 21 – What happens when an electric current is passed through a cut potato for a considerable time? (2 Marks)
Q 22 – What is electroplating? What are its uses? (3 Marks)
Q 23 – What happens when an electric current is passed through the copper sulphate solution? (3 Marks)
Q 24 – Does water conduct electricity? Show with the help of an activity. (4 Marks)
Q 25 – With the help of a suitable diagram, explain the electrolytic refining of copper. (4 Marks)