a battery has internal resistace of 4ohm and the emf is 12v .The battery used to maintain a current in a resistor of resistance of 20 ohm
a)Calculate the current in the circuit
b)the potential difference across the ends of the 20 ohm resistor and the energy transformed in the 20 ohm resitor
current in circuit:
12/(24) = .5 amp
potential on resister
.5a*20ohm=10volts
energy= I^2 R= .25*20=5 watts
To calculate the current in the circuit, you can use Ohm's law. Ohm's law states that the current (I) flowing through a circuit is equal to the voltage (V) divided by the resistance (R). In this case, the voltage is the electromotive force (EMF) of the battery and the resistance is the sum of the internal resistance (r) and the resistance of the external resistor (R).
a) Calculate the current in the circuit:
First, let's calculate the total resistance (RT) of the circuit by adding the internal resistance (r) and the resistance of the external resistor (R):
RT = r + R = 4 Ω + 20 Ω = 24 Ω
Now, we can use Ohm's law to calculate the current (I):
I = V / R = 12 V / 24 Ω = 0.5 A (Amperes)
Therefore, the current flowing through the circuit is 0.5 Amperes.
b) To calculate the potential difference across the ends of the 20 Ω resistor, you can use Ohm's law again. The potential difference (V) across a resistor is equal to the current (I) flowing through it multiplied by the resistance (R).
First, let's find the current flowing through the 20 Ω resistor. Since the current is already calculated as 0.5 A, we can use that value.
Then, calculate the potential difference:
V = I * R = 0.5 A * 20 Ω = 10 V
Therefore, the potential difference across the ends of the 20 Ω resistor is 10 Volts.
To calculate the energy transformed in the 20 Ω resistor, we can use the formula E = V * I * t, where E is the energy, V is the potential difference, I is the current, and t is the time.
Since the time is not given in the question, we cannot directly calculate the energy.