PHY 1122 Chapter Notes - Chapter 3: Nichrome, Heating Element, Temperature Coefficient

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amethystgerbil872

3 Mar 2015

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A wire of length 1. 0 m has a resistance of 0. 3 . A 6. 50- resistor is made from a coil of copper wire whose total mass is 18. 0 g. The density and resisitivity of copper are, respectively, 8. 90 103 kg/m3 and 1. 72. The curve that best represents the power loss in a resistor is. A heating element made of nichrome wire (temperature coefficient of resistivity . = 0. 400 10-3 k-1) is connected to a source. When it has just been turned on and its temperature is 20 c, it dissipates 960 w of power. What power is dissipated when its temperature has risen to 300 c: 1, 2, 3, 4, 5. Answer: c: 1. 1 103 w, 9. 6 102 w, 8. 6 102 w, 8. 6 103 w, 1. 1 102 w. Rank the bulbs in the circuits in the order of brightness. Answer: a = d = e > b = c. Rank the bulbs in the circuit in order of brightness.

Related Questions

True orFalse?

1. Theresistance of a metal rod depends on temperature.

2. Theresistance of a metal rod does not depend onitsconductivity.

3. Theresistance of a metal rod with fixed cross-sectionalarea dependson the shape of the cross sectional area.

4. Acylindrical copper rod has resistance R. It is reformed totwiceits original length with no change of volume. Its newresistance isequal to 2R.

5. Acertain wire has a resistance R. Another wire, made of thesamematerial, has half the length and half the diameter of thefirstwire. The resistance of the second wire is equal toR.

1. The drawing shows two long, straight wires thataresuspended from the ceiling.

The mass per unit linglh of each wire is 0.050 kg/m. Eachofthe four strings suspending

the wires has a length of 1.2 m. When the wires canyidenticalcurrents in opposite

directions, the angle between the strings holding the twowiresis 15Â° What is the current

in each wire?

2. A piece of copper wire has a resistance per unitlength 6.0x l0 ^-3 Î© /m. The wire is wound into athin, flat coil of manyturns that has a radius of 0.15 m. Theends of the wire areconnected to a 12 V battery. Find themagnetic field strength at thecenter of the coil.

3. A conducting coil of 1800 turns is connected toagalvanometer, and the total

resistance of the circuit is 50 Î©. The area of eachtum is 5.2x 10 ^-4 m². The coil is

moved from a region where the magnetic field is zero intoaregion where it is nonzero,

the normal to the coil being kept parallel to themagneticfield. The amount of charge

that is induced to move around the circuit is measured tobe9.0 x l0^-3 C. Find the

magnitude of the magnetic field.

[Such a device can be used to measure the magneticfieldstrength in a region of space and is called afluxmeter.]

1)As shown in the figure, a uniform conducting rod of length 0.40 m and mass 0.075 kg is in rotational equilibrium about the hinge at point O. A uniform magnetic field of 0.23 T is directed out of the plane of the page, perpendicular to the rod. Due to a battery and wires not shown, there is a current of 4.0 A in the rod directed toward point O. Determine the angle θ.

2)As shown in the figure, a conducting rod with a length of 0.79 m is placed on a horizontal frictionless surface and attached to a power supply by two springs, each with a spring constant of 81 N/m. The springs are initially at their equilibrium length and are in a region where there is a uniform magnetic field of 0.17 T that is perpendicular to the frictionless surface when the power supply supplies a current that causes the wire to move in such a direction that the two springs are stretched.