Very easy physics maths about current and other stuffs only one question please help me

Three identical resistors of resistance 3 ohms are connected in series in a circuit. What is the total voltage of the battery if the current in the circuit is 2A ?

Total voltage of the battery is 12 volts.

Explanation:

It is given that, we have three identical resistors of resistance 3 ohms are connected in series in a circuit. It is required to find the total voltage of the battery if the current in the circuit is 2 A.

Let is the equivalent resistance in series combination. The equivalent resistance is given by :

Let V is the total voltage of the battery. Ohm's law is given by :

So, the total voltage of the battery is 12 volts.

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

the answer is b ) square root of 5