Calculate Current Through Battery Connected to Resistor

• katiemc124
In summary, the question involves removing a voltmeter that reads 12 V from a battery and connecting a 21 ohm resistor. The task is to find the current through the battery, but there is not enough information provided to solve the problem accurately. The solution would require the internal resistance of the battery, which is not given.
katiemc124

Homework Statement

The voltmeter is removed (previous question was a voltmeter connected to a battery and it reads 12 V) and a resistor of 21 ohm is connected to the battery. What is the current (I) through the battery?

emf=V
I=emf/(R+r)

The Attempt at a Solution

I tried to do I=12V/21 ohm but I don't know how to find R. When I entered the solution of that, it said to include the internal resistance of the battery, but I don't know the current of the battery so I can't use emf=IR to find R.

Is there an answer in the back of the book to compare to?

haha nevermind. I was having trouble because I didn't have enough information, but I just didn't see where it was written. Thanks for your help anyway!

1. How do you calculate the current through a battery connected to a resistor?

The current through a battery connected to a resistor can be calculated using Ohm's Law, which states that current (I) is equal to the voltage (V) divided by the resistance (R). The formula is written as I = V/R.

2. What is the unit of measurement for current?

The unit of measurement for current is ampere (A), which is defined as the flow of one coulomb of charge per second.

3. How does the resistance of the resistor affect the current?

The resistance of the resistor directly affects the current. As the resistance increases, the current decreases and vice versa. This is because a higher resistance makes it more difficult for the electrons to flow through the circuit, resulting in a lower current.

4. Can the current through a battery connected to a resistor ever be higher than the battery's voltage?

No, the current through a battery connected to a resistor cannot be higher than the battery's voltage. The current is limited by the battery's internal resistance and the resistance of the external circuit. However, if the battery is connected to a circuit with no resistance, the current will be very high and can potentially damage the battery.

5. How do you calculate the power dissipated by the resistor?

The power dissipated by the resistor can be calculated using the formula P = I^2 * R, where P is power in watts, I is current in amperes, and R is resistance in ohms. This formula is derived from the equation for power, P = V * I, where V is voltage. However, since Ohm's Law can be used to find the value of I, the formula can also be written as P = (V^2)/R.

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