Chapter 27: Q. 31 (page 763)

The terminals of a $0.70 V$ watch battery are connected by a $100 m$ long gold wire with a diameter of $0.10 mm$ . What is the current in the wire?

Short Answer

Expert verified

The current in the wire is $2.29 m A$ .

Step by step solution

Given Information

Voltage $= 0.70 V$

Gold wire length $= 100 m$

Diameter $= 0.10 m m$

Explanation

If we can calculate the potential difference across the wire and the resistance, we can find the current according to Ohm's law.

$I = \frac{U}{R} \to (1)$

The resistance of the conductor appears in the following expression:

$R = ρ \frac{L}{A} \to (2)$

Substituting the second expression into the first one,

$I = \frac{A U}{ρ L} .$

The cross-section area is a circle, we can substitute $A = \frac{π D^{2}}{4}$ to find

$I = \frac{π U D^{2}}{4 ρ L}$

Substitute the expression,

role="math" localid="1649055691425" $I = (\frac{π \times 0.7 V \times 0 . 0001^{2} m m}{4 \times 2.4 \times 10^{- 8} Ω m \times 100 m})$

$I = 2.29 mA$

Final Answer

Hence, the current in the wire is $2.29 m A .$

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The terminals of a $0.70 V$ watch battery are connected by a $100 m$ long gold wire with a diameter of $0.10 mm$ . What is the current in the wire?

Short Answer

Step by step solution

Given Information

Explanation

Final Answer

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The terminals of a 0.70V watch battery are connected by a 100m long gold wire with a diameter of 0.10mm. What is the current in the wire?

Short Answer

Step by step solution

Given Information

Explanation

Final Answer

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Physics Textbooks

Nuclear Physics

Quantum Physics

Famous Physicists

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Electrostatics

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Study anywhere. Anytime. Across all devices.

The terminals of a $0.70 V$ watch battery are connected by a $100 m$ long gold wire with a diameter of $0.10 mm$ . What is the current in the wire?