When an electric current is passed through a conducting solution, there is a change of colour of the solution. This indicates
  • the chemical effect of current.
  • the heating effect of current.
  • the magnetic effect of current.
  • the lightning effect of current.
the electrode connected to the negative terminal of a battery is known as
  • anode
  • negative pole
  • cathode
  • electrolyte
The electrodes are generally made up of
  • rubber
  • plastic
  • carbon
  • wood
During electrolysis of water, hydrogen gas is deposited at which electrode?
  • Positive electrode
  • Negative electrode
It is dangerous to touch electrical appliances with wet hands because water is a
  • good conductor of electricity
  • bad conductor of electricity
  • colourless liquid
In LEDs, the longer lead (wire) is always connected to the _______ terminal
  • positive
  • negative
  • any
When electrodes are immersed in water and electricity passed, the bubbles formed on the positive terminal is actually _______ gas.
  • (a) Hydrogen
  • (b) Carbon dioxide
  • (c) Oxygen
  • (d) Nitrogen
While testing fruits and vegetables for conductivity, a student inserted the copper wire ends of a tester into cut half of potatoes a colour change is observed:
  • greenish blue spot around both electrodes
  • greenish blue spot around the negative electrode
  • greenish blue spot around the positive electrode
  • no colour change is seen
A chemist had shown that if electrodes were immersedin water, and a current was passed, bubbles of oxygenand hydrogen were produced. This scientist was:
  • William Nicholson
  • Michael Faraday
  • Alessandero Volta
  • John Frederic Daniell
2. Why is it better to use a light – emitting diode (LED) rather than a light bulb when testing the electrical conductivity liquids?
  • a. An LED glows even when a weak electric current flows in a circuit
  • b.LEDs do not melt even when a high electric current flows in a circuit
  • c.LEDs are environment friendly
  • d. LEDs are cheap
3. Firemen shut off the electricity supply for the area before using water hoses to douse a fire. Why?
  • a.To prevent the fireman from being electrocuted because ordinary water is a conductor electricity
  • b. To prevent electrical devices from being spoilt.
  • c. To reduce electricity usage
  • d. To prevent the fire from spreading
4. When an electric current flows through a conducting solution, it can produce which of the following effects?
  • a. Bubbles of gas on the electrodes
  • b. Deposits of metal on the electrodes
  • c. A change in the colour of the solution
  • d. All the above.
Boojho and Paheli performed experiments taking similar bulbs and cells but two different solutions A and B as shown in the figure.They found that the bulb in the setup A glows more brightly as compared to that of the setup B. You would conclude that
  • (a) higher current is flowing through the circuit in setup A.
  • (b) higher current is flowing through the circuit in setup B.
  • (c) equal current is flowing through both the circuits.
  • d) the current flowing through the circuits in the two setups cannot be compared in this manner.
In Liquids, Electricity flows because of the movement of
  • Protons
  • Neutrons
  • Electrons
  • Ions
there are __________ types of effects of electric current
  • 5
  • 4
  • 3
  • 2
When electric current passes through a conducting solution, it causes _______ _______
  • chemical reactions
  • light effect
  • magnetic effect
  • nucleus reaction
Who discovered chemical effect of elecric current?
  • Thomas Edison
  • Joule-Lenz
  • Michael Faraday
  • James Watt
Who discovered heating effect of elecric current?
  • James Watt
  • Joule-Lenz
  • Michael Faraday
  • Thomas Edison
Tick the electric apps working with mechanical effect of electric current
  • Juice squeezer
  • Electric oven
  • Compass
  • Electric kettle
When an electric current pass through by the conductors, the conductor ___________ ______
  • to begin crash
  • going to freeze
  • heats up
  • going to melt
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