if a cell supplies a current of 0.5a when it's emf is 2v and internal resistance is 1 ohms calculate it's external resistance a). 0.5ohms b). 1ohms c). 2ohms d). 2.5ohms e). 3ohms?
I*r + I*R = 2 volts.
0.5*1 + 0.5R = 2,
R = 3 ohms.
Ohm my, let me calculate this hilariously electrifying problem for you! We're given that the emf of the cell is 2V and the internal resistance is 1 ohm. To find the external resistance, we can use Ohm's Law: V = IR.
The current supplied by the cell is 0.5A, so if we rearrange the formula, we get R = V/I. Plugging in the values, we have R = 2V / 0.5A, which gives us 4 ohms. So the answer is not among the options you've listed. I guess the real joke here is that none of the choices make the cut! Keep laughing with me!
To find the external resistance, we can use Ohm's Law and the concept of internal resistance.
Ohm's Law states that the current (I) flowing through a circuit is equal to the voltage (V) across the circuit divided by the total resistance (R):
I = V / R
In this case, the current (I) is given as 0.5 A (0.5 Amperes), the EMF (V) is given as 2 V (2 Volts), and the internal resistance (r) is given as 1 Ω (1 Ohm).
The total resistance (R) in the circuit can be calculated as the sum of the external resistance (R_ext) and the internal resistance (r):
R = R_ext + r
Rearranging the equation, we get:
R_ext = R - r
Substituting the given values, we have:
R_ext = 0.5 Ω - 1 Ω
R_ext = -0.5 Ω
Since resistance cannot be negative, this implies that the given values are not physically possible. Therefore, none of the provided options (a, b, c, d, or e) is correct.
To calculate the external resistance, we can use Ohm's Law, which states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to the resistance.
Let's denote the external resistance with the letter R(ext) and the total resistance (combination of internal and external resistance) with the letter R(total).
We know that the current supplied by the cell is 0.5A (amperes), the electromotive force (EMF) is 2V, and the internal resistance is 1Ω (ohm).
Using Ohm's Law, we can write the equation as follows:
EMF = Current * (R(internal) + R(ext))
Substituting the known values:
2V = 0.5A * (1Ω + R(ext))
Now we can solve for R(ext):
2V = 0.5A * (1Ω + R(ext))
Divide both sides by 0.5A:
4Ω = 1Ω + R(ext)
Subtract 1Ω from both sides:
3Ω = R(ext)
Therefore, the external resistance is 3 ohms (option e).