Question:
Two bars of radius r and 2rare kept in contact as shown. An electric current I is passed through the bars. Which one of following is correct ?
Two bars of radius r and 2rare kept in contact as shown. An electric current I is passed through the bars. Which one of following is correct ?
Updated On: Jun 23, 2023
- Heat produced in bar BC is 4 times the heat produced in bar AB
- Electric field in both halves is equal
- Current density across AB is double that of across BC
- Potential difference across AB is 4 times that of across BC
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The Correct Option is A
Solution and Explanation
Current flowing through both the bars is equal.
Now, the heat produced is given by
$H = I^2 Rt \, or H ? R \, or \frac{H_{AB}}{H_{BC}}= \frac{R_{AB}}{R_{BC}}$
$= \frac{(1/2r)^2}{(1/r)^2} \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \big( as \, R ? \frac{1}{A} ? \frac{1}{r^2}\big)$
$= \frac{1}{4} \, or \, H_{BC} = 4H_{AB}$
Now, the heat produced is given by
$H = I^2 Rt \, or H ? R \, or \frac{H_{AB}}{H_{BC}}= \frac{R_{AB}}{R_{BC}}$
$= \frac{(1/2r)^2}{(1/r)^2} \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \big( as \, R ? \frac{1}{A} ? \frac{1}{r^2}\big)$
$= \frac{1}{4} \, or \, H_{BC} = 4H_{AB}$
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Concepts Used:
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The current electricity that is bidirectional and keeps changing the direction of the charge flow is known as alternating current. The bi-directionality is caused by a sinusoidally varying current and voltage that reverses directions, creating a periodic back-and-forth motion for the current. The electrical outlets at our homes and industries are supplied with alternating current.