Question

In the house of a person who is weak in hearing, a light bulb is also lit when somebody rings the doorbell. The ring can be operated both from the garden gate and from the door of the house. Select the correct possible circuit(s) required.
A)
B)

C)

D)

Answer 1

When appliances connected in parallel then current flowing through them is different but potential difference or voltage across them is the same. And in the case of series connection, current flowing through them is the same and potential difference is different.

Complete step by step answer:
In a parallel circuit, the voltage across each of the components remains the same, and the total current is the sum of the currents through each component. If one of the components in the parallel connection goes wrong, the other components will function without any hindrance. Therefore, in this case, there are two switches in the circuit, one on the door and one on the gate. Both the switches are connected in parallel and then, the bell and the light bulb are connected in parallel. Each component operates independently of each other and can function if any one of the components goes wrong.

Hence, circuit B is correct

Additional information:
Every electrical appliance will have rated or design values like wattage, voltage printed on it. These values give information about resistance and allowable current etc.., let $P$ and $V$ be the power and voltage rating on a bulb.
As the three bulbs are connected in parallel, the voltage applied across them would be the same, let us consider as $V$ and current through each of them is different.
Now, due to the fact that the power dissipated by the three bulbs is different, also the current flowing through them would be different and thus they will have different brightness.
We know that the brightness of the bulb is directly proportional to the power it uses or the amount of current it draws.

Note:
When appliances are connected in parallel then current flowing through them is different but potential difference or voltage across them is the same. And in the case of series connection, current flowing through them is the same and potential difference is different.
In parallel connection, if one appliance gets fused the other will work.