# 1) A 25. meter long wire, of diameter 0.30 mm, con…

### Question Description:

20.50

1) A 25. meter long wire, of diameter 0.30 mm, connected to 3.00 volts draws 0.499 A. (a) What is the resistance of the wire? (b) What is its resistivity? (c) What is its conductivity? 2) A Tungsten wire is 1.50 m long and has a diameter of 1.00 mm. At 20.°C a current of 50. mA flows through the wire.[alfpa =0.0045(C°)-1] (a) Determine the potential across the wire. (b) If the wire temperature increases by 100. C°, what potential is now required to produce a current of 50. mA? 3 A heating element of resistance (at its operating temperature) 185 omega is connected to a battery of emf 425 V and unknown internal resistance r. It is found that heat energy is being generated in the heater element at a rate of 68.0 W. What is the rate at which heat energy is being generated in the internal resistance of the battery? 4) When an external resistor of resistance R1 = 14omega is connected to the terminals of a battery, a current of 6.0 A flows through the resistor. When an external resistor of resistance R = 64.4omega is connected instead, the current is 2.0 A. Calculate: (a) the emf of the battery and (b) the internal resistance of the battery