Textbook Question
Electrical engineers sometimes use a wire's conductance, G=σA/L, instead of its resistance. What is the conductance of a 5.4-cm-long, 0.15-mm-diameter tungsten wire?
27. Resistors & DC Circuits
Resistors and Ohm's Law
Back27. Resistors & DC Circuits
Resistors and Ohm's Law
- Textbook Question
A 0.0075 V/m electric field creates a 3.9 mA current in a 1.0-mm-diameter wire. What material is the wire made of?
1views - Textbook Question
A sequence of potential differences V is applied across a wire ( diameter = 0.32 mm, length = 11cm) and the resulting currents I are measured as follows: Plot I vs. V. Based on this plot, can you conclude that the wire obeys Ohm’s law (i.e., did you obtain a straight line with the expected y-intercept, within the values of the significant figures)? If so, determine the wire’s resistance R.
- Multiple Choice
A resistor has a current through it of 5 A. If the EMF across the resistor is 10 V, what is the resistance of this resistor?
2views - Textbook Question
Compute the voltage drop along an 18-m length of household no. 14 copper wire (used in 15-A circuits). The wire has diameter 1.628 mm and carries a 12-A current.
- Textbook Question
(II) An ammeter whose internal resistance is 53 Ω reads 5.25 mA when connected in a circuit containing a battery and two resistors in series whose values are 760 Ω and 480 Ω. What is the actual current when the ammeter is absent?
- Textbook Question
A galvanometer has an internal resistance of 32 Ω and deflects full scale for a 48-μA current. Describe how to use this galvanometer to make an ammeter to read currents up to 25 A.
- Multiple ChoiceA certain wire has length L and radius r, and a resistance of R. That wire is melted down and the same volume of the same metal is used to produce a wire with length 2L. What is the resistance of the resulting wire?1views
- Textbook Question
Household wiring has sometimes used aluminium instead of copper. What would be the resistance of the same wire if it were made of aluminum?
1views - Textbook Question
Calculate the terminal voltage for a battery with an internal resistance of 0.900 Ω and an emf of 6.00 V when the battery is connected in series with a 61.0-Ω resistor.
- Multiple ChoiceA copper wire with a radius of and a length of is connected across the terminals of a battery. How much current flows in the wire?1views
- Multiple ChoiceA copper wire and an aluminum wire have the same diameter. If the copper wire is long, how long is the aluminum wire if they have the same resistance?
- Textbook Question
(a) What is the equivalent resistance of the circuit shown in Fig. 26–80? (b) What is the current in the 18-Ω resistor? (c) What is the current in the 12-Ω resistor? (d) What is the power dissipation in the 4.5-Ω resistor?
- Textbook Question
An engineer cuts a 1.0-m-long, 0.33-mm-diameter piece of wire, connects it across a 1.5 V battery, and finds that the current in the wire is 8.0 A. Of what material is the wire made?
- Textbook Question
What is the resistance of a 5.1-m length of copper wire 1.5 mm in diameter?