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1. In the circuit shown, a 20Ω resistor is inside 100 g of water that is surrounded by an insulator.
If the water is initially at 10â—¦C how long will it take for the temperature to rise to 58â—¦C?
2. In the circuit shown, find:
(a) The current in the 3Ω resistor.
(b) The unkown emf’s E1 and E2.
(c) The resistance R. Note the three currents given.
3. A long copper rod of radius R carries a constant current I, with the current density (current
per unit area) J→ uniform over its cross section. Compute the value of the magnetic field B(r)
at all values of radius r from the center of the rod (there are two regions: r < R> R).
4. A semi-circular wire of radius R, carrying a current I, is placed in a constant magnetic field
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