MCQs on Electric Circuits

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01․ During electroplating the weight of substance deposited depends on
shape of article.
quantity of electricity.
room temperature.
atmospheric humidity.

According to the Faraday's first law of electrolysis, the mass of the chemical deposition due to the flow of current through an electrolyte is directly proportional to the quantity of electricity passed through it. So, the weight of the chemical deposition depends on the quantity of electricity.

02․ Zinc cadmium and lead coating is generally provided for
electrical contacts.
all of above.

The zinc, cadmium and lead are the anodic to iron and its corrosion rate is very less. It provides relatively long term protection for the cast irons from the corrosion. So, these coatings are generally provided for corrosion.

03․ Which of the following substance when added to electrolyte promotes smooth deposition?
Any of above.

The above substances are smooth in nature. During the electroplating process, the high current density is too high. Thus, there is a chance of forming the hard surface. So, when the substances are added to the electrolyte solution, it promotes the smooth deposition.

04․ Addition of which of the following substance in electrolyte helps in producing bright finish?
Any of above.

These three materials are used to remove the waste particles after finishing the electroplating process by feeding the object into those solutions. Hence, finally it produces the bright finish.

05․ During electroplating the amounts of different substances liberated by same quantity of electricity are proportional to their
chemical equivalents.
atomic weights.
atomic numbers.

According to the Faradays second law, the amounts of different substances liberated by the same quantity of electricity are proportional to their chemical equivalent weights.

06․ Lowest current density is generally recommended for plating of

The melting point of the silver metal is less than the other above shown materials. If the current density is very high, then the temperature generation in the electrolyte is also too high. So, it is not suitable for silver. That is why the lowest current density is generally recommended for the silver plating.

07․ Energy efficiency during electroplating is usually in the range
50 to 80%.
80 to 85%.
85 to 90%.
90 to 99%.

The energy efficiency is usually very less in the range of 50 to 80% because in the electroplating process, other reactions occur such as the evolution of hydrogen when the applied voltage increases which eventually reduces the system's overall energy efficiency.

08․ Which metal is deposited for electro forming?

In the basic electroforming process, an electrolytic bath is used to deposit nickel or other electro - formable metals like copper, silver or chromium onto a conductive patterned surface such as stainless steel and iron.

09․ Container of a lead acid battery
molded hard rubber.
any of above.

The container of the battery must be mechanically very strong and there should not be any leak. These are all the major things that we are considered while making a battery container. Hence, the above mentioned all the three material can provide the mechanical strength to the container because all the material are basically strong in nature.

10․ Active materials of a lead acid cell are
spongy lead.
lead peroxide.
dilute H2SO4.
all of above.

The materials which participate in the electrochemical charge and discharge reaction are called as active elements of a lead acid cell. These materials include electrolyte and the positive and negative electrodes. We know that the dilute H2SO4 is electrolyte of lead acid cell, the sponge lead is negative electrode and the lead peroxide is the positive electrode. Hence, all of the above are active materials of a lead acid cell.