Given that,
Resistance, R = 30 ohms
Current, I = 10 A
To find,
The voltage of the battery.
Solution,
Let V is the voltage of the battery. We can use Ohm's law to find V.
Since, V = IR
Put all the values in the above formula.
V = 10×30
V = 300 Volt
So, the voltage of the battery in the voltmeter is 300 Volt.