32.Alpha.The temperature coefficient of resistivityαof a certain Ohmic material is defined asthe ratio of the fractional change in resistivityΔρ/ρ0to the absolute change in temperatureΔT. Given the resistivity data below for three conductors X, Y, and Z, which among thechoices is the correct order according toincreasingα?
A – 10
First Problem Set
First Semester, AY 2015–2016
Physics 72
Conductor
Resistivity (
10

8
Ω m
) at
T
= 20
◦
C
Resistivity (
10

8
Ω m
) at
T
= 50
◦
C
X
100
120
Y
50
100
Z
200
250
A. X<Y<ZB. Z<Y<XC. Y<X<ZD. X<Z<Y
33.Across the Universe.Which of the following statements is/areALWAYS TRUE?I. The IV curve of a nonohmic material is linear.II. The IV curve of an ohmic material is increasing.III. The IV curve of an ohmic material is logarithmic.
34.Resistivity.A cylindrical conductor has resistivityρ, lengthLand radiusr. By how muchshouldLbe increased/decreased if we were to quadruple the cylindrical conductor’s radiusin order to maintain its resistance?
35.Power Dissipation.A50.0 Ωbulb is connected across the terminals of a10.0 Vbatterywith an internal resistance of5.00 Ω. What percentage of the power of the battery is dissipated across the internal resistance and hence is not available to the bulb?
For the next two items, consider the circuit shown.
36.Current.What is the currentI1?
A – 11
First Problem Set
First Semester, AY 2015–2016
Physics 72
A.6.0 mAB.2.0 mAC.6.0 mAD.2.0 A
37.Voltage.What is the voltage across the1.0kΩresistor?
Consider the network of identical resistors with resistance
6
.
00 Ω
and current
I
1
=
2
.
00 A
passing through
R
1
as
shown.
38.Sa lahat ng oras...What is the equivalent resistance ofthe network?
39....sila’y magkasama.What is current passing throughR3?
40.Mega 800.A circuit contains a1μFcapacitor, an8 Vemf source, and a100 Ωresistorconnected in series. If the resistor was replaced with10 Ω, which of the following wouldhappen?I. The current in the circuit approaches zero more slowly.II. The charge of the capacitor approaches its maximum value more quickly.III. The power dissipated by the resistor approaches its maximum value more quickly.
A. II onlyB. I and III onlyC. II and III onlyD. I, II and III
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