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If the currents in the three parallel branches of an ac circuit are given as I1 = 25∠30°A, I2 = 25e-jΠ/6A and I3 = (50 + j 50)A, express the total current in the form
(i) I ∠Φ and
(ii) Im sin (ωt + Φ).
Draw the phasor diagram and find the sum of the currents: i1=141.42 Sin(t + /2) , i2 = -70.71 Cos t , i3= 50 ej/3 , i4=100 -2/3 and i5= 50 (Cos /3 + j Sin/3)
A parallel plate capacitor has an area of 5.00 cm2 and a capacitance of 3.50 pF. The capacitor is connected to a 12.0 V battery. After the capacitor is completely charged up, the battery is removed
a. What must be the separation of the plates and how much energy is stored in the electric field between the plates?
b. If a sheet of Mica with εr=3.5 is placed between the plates, how will the voltage across the plates and the charge density on the plates change?
c. If the sheet of Mica has an area of 3.00 cm 2 so that it does not cover the whole area of the plates, what would be the effective capacitance of this arrangement?
d. If the Mica sheet is removed and the plates are moved 1.00 mm farther from each other, what will be the voltage between the plates, and how much work will it take to move the plates apart?
A parallel plate capacitor has an area of 5.00 cm2 and a capacitance of 3.50 pF. The capacitor is connected to a 12.0 V battery. After the capacitor is completely charged up, the battery is removed
a. What must be the separation of the plates and how much energy is stored in the electric field between the plates?
b. If a sheet of Mica with εr=3.5 is placed between the plates, how will the voltage across the plates and the charge density on the plates change?
c. If the sheet of Mica has an area of 3.00 cm 2 so that it does not cover the whole area of the plates, what would be the effective capacitance of this arrangement?
d. If the Mica sheet is removed and the plates are moved 1.00 mm farther from each other, what will be the voltage between the plates, and how much work will it take to move the plates apart?
A 500 m long wire has a resistance of 20 Ω. How much must be cut off to reduce its resistance to 12 Ω?
The temperature coefficient of resistance for carbon at 0℃ is -0.00048/℃.What is the significance of the minus sign? A carbon resistor has a resistance of 500 Ω at ℃. Determine it's resistance at 50 ℃?
Some aluminum wire has a resistance of 50 Ω at 20 ℃. The wire is heated to a temperature of 100 ℃. Determine the resistance of the wire at 100 ℃, assuming that the temperature coefficient of resistance at 0℃ is 1/250 per ℃?
Find the length of a piece of nichrome wire 0.5 mm in diameter which has a resistance of 30.52 Ω. The specific resistance of nichrome wire is 109 µΩcm?
A cable has a resistance of 10.5 Ω. What will be the resistance of another cable of the same material twice as long and half the cross-section area?
An aluminum wire 7.5 m long is connected in parallel with a copper wire 6 m long. When a current of 5A is passed through the combination, it is found that the current in the aluminum wire is 3A.The diameter of the aluminum wire is 1.0 mm.Determine the diameter of the copper wire. Resistivity of copper is 0.0017 µΩ m; that of aluminum is 0.028 µΩm?
