Question

In charging a battery of a motor car, which of the following effects of electric current is used?
$
  (a){\text{ heating}} \\
  {\text{(b) magnetic}} \\
  {\text{(c) chemical}} \\
  {\text{(d) induction}} \\
 $

Answer 1

Hint – In this question use the basic concept of charging that is the entity that is to be charged must be at a lower potential in comparison to the source because flow of electrons will always form a higher potential towards a lower potential. The energy that flows between the source and the body to be charged is stored in the form of chemical energy. This will help approach the question to get the right answer.

Complete step-by-step answer:

As we know that flow of electrons is always from higher voltage source to lower voltage source.
In case of battery charging of a motor car the source voltage must be greater than the battery voltage otherwise reversal of flow of electrons is happened.
In this case the battery behaves as a source so the direction of the current is reversed.
So source voltage is always greater than the battery voltage to charge the battery.
The energy which is the product of voltage, current and time is stored in the battery in the form of chemical energy.
I.e. It is based on the conversion of electric energy into chemical energy.
According to conservation of energy, energy can neither be created nor be destroyed; it is only converted from one form into another form.
The positive terminal of the car battery is connected to the positive terminal of the source and the negative terminal of the car battery is connected to the negative terminal of the source as shown in the figure.
Rate of charging the battery is dependent on the voltage difference of the source voltage and the battery voltage, higher the difference, higher the rate of charging.
But there is an issue of over-charging and this leads to damage to the battery.
Hence in charging the battery of a motor car chemical effect of electric current is used.
So this is the required answer.
Hence option (C) is the correct answer.

Note – Heating will always be there whenever there is a flow of electrons but however it only leads to the loss of energy and has no significance in charging. When the electrons moving between two different potentials collide with each other there is a loss of kinetic energy and this accounts for production of heat in the system.