Worksheetschemical effects of current
Total questions: 30
Worksheet time: 23mins
An electric current can produce
heating effect only.
chemical effect only.
magnetic effect only.
chemical, heating, and magnetic effects.
Boojho’s uncle has set up an electroplating factory near his village. He should dispose off the waste of the factory
in the nearby river.
in the nearby pond.
in the nearby cornfield.
according to the disposal guidelines of the local authority.
Which one of the following solutions will not conduct electricity?
lemon juice
vinegar
tap water
vegetable oil
Which of the following metals is used in electroplating to make objects appear shining?
iron
aluminium
copper
chromium
Which of the following solutions will not make the bulb in Fig 14.2 glow?
(a)
(b)
(c)
(d)
sodium chlorides
copper sulphate
silver nitrate
sugar solution in diluted water
Tick the chemical effect of elecric current
boiling
motion
electro shock
Electroplating
LED stands for
light emitting diode
light efficient diode
length emitting diode
light emitting device
Adding common salt to distilled water makes it
Good Conductor
Poor Conductor
No change
Both A and B
An electrolyte is
a metal
a solution
a liquid that conducts electricity
none of these
the phenomenon of decomposition of an electrolyte when electricity is passed through is known as
conduction
coating
electrolysis
electrorefining
The object to be electroplated is taken as ____________ electrode.
cathode
anode
electrode
none of these
one of the following is not used for electroplating metal articles. the one is -
nickel
chromium
sodium
silver
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
Chromium corrodes easily.
True
False
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
Why do we add little dilute sulphuric acid to copper sulphate solution during electroplating?
To burn copper sulphate
So that the colour becomes more prominent
To increase conductivity
To increase basicity
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 immersed
in water, and a current was passed, bubbles of oxygen
and 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
