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Ratio of current flowing through the wir...

Ratio of current flowing through the wire. If both the wire have same area and the ratio between their length is 4:1.

A

`1:1`

B

`1:4`

C

`4:1`

D

`4:4`

Text Solution

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The correct Answer is:
To solve the problem of finding the ratio of current flowing through two wires with the same area but different lengths, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding Ohm's Law**: According to Ohm's law, the relationship between voltage (V), current (I), and resistance (R) is given by: \[ V = I \times R \] For two wires, if the potential difference across both wires is the same, we can write: \[ V = I_1 \times R_1 = I_2 \times R_2 \] 2. **Finding the Ratio of Currents**: From the above equation, we can express the ratio of the currents as: \[ \frac{I_1}{I_2} = \frac{R_2}{R_1} \] 3. **Calculating Resistance**: The resistance \( R \) of a wire is given by the formula: \[ R = \frac{\rho L}{A} \] where \( \rho \) is the resistivity, \( L \) is the length of the wire, and \( A \) is the cross-sectional area. 4. **Substituting for Resistance**: For our two wires, we can write: \[ R_1 = \frac{\rho L_1}{A} \quad \text{and} \quad R_2 = \frac{\rho L_2}{A} \] 5. **Cancelling Common Terms**: Since both wires have the same material (same resistivity) and the same area, we can cancel \( \rho \) and \( A \) from the ratio: \[ \frac{I_1}{I_2} = \frac{R_2}{R_1} = \frac{L_2}{L_1} \] 6. **Using the Given Length Ratio**: We are given that the ratio of their lengths is \( L_1 : L_2 = 4 : 1 \). This means: \[ L_1 = 4L \quad \text{and} \quad L_2 = L \] Therefore, the ratio \( \frac{L_2}{L_1} \) can be expressed as: \[ \frac{L_2}{L_1} = \frac{L}{4L} = \frac{1}{4} \] 7. **Final Ratio of Currents**: Substituting back into our earlier equation gives us: \[ \frac{I_1}{I_2} = \frac{L_2}{L_1} = \frac{1}{4} \] Thus, the ratio of currents \( I_1 : I_2 \) is: \[ I_1 : I_2 = 1 : 4 \] ### Conclusion: The ratio of the current flowing through the two wires is \( 1 : 4 \).

To solve the problem of finding the ratio of current flowing through two wires with the same area but different lengths, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding Ohm's Law**: According to Ohm's law, the relationship between voltage (V), current (I), and resistance (R) is given by: \[ V = I \times R \] ...
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