Reading: All sections

Problems: C1, C6, C9, 1.2, 2.5, 9.1, 9.2

Electric Fields – Chapter 24

Reading: All Sections

Problems: C6, 1.3, 1.4, 2.2, 6.2, 6.3

All problems due in class on: Friday, April 23rd

DC Circuits

The lab uses two different light bulbs (let the spherical bulbs be type A and the “elongated” bulbs type B).  You will need 2 A’s and a B.  The energy source is two D batteries in series.

A.            Resistances of the Light Bulbs

1.            How must a voltmeter and ammeter be connected in a circuit?

2.            What has more resistance, a 60-watt or 100-watt light bulb?

3.            Apply Ohm’s law to determine the resistances of your A and B bulbs and determine the power consumed by each.  Noticing which burns brighter, is this consistent with what we have discussed?

Initial Sign-off __________

B.            Light Bulbs in Series

The goal is to determine whether the input voltage equals the sum of the voltages in a loop.

1.         Connect two A’s in series with the batteries.  Measure the output voltage across the batteries and that across each light bulb.  Is what you measured consistent with what you know/expect about series circuits?  Explain.  Also explain any inconsistencies with theory.

2.         If a single A bulb is connected to the batteries, how does its brightness compare with that of 2 in series?  Explain.

3.         With two A’s in series, measure the current.  Is Ohm’s law satisfied (recall that you have determined the resistances of the bulbs)?  Explain any inconsistencies.

4.         Connect an A and a B in series with the batteries and explain what you see.  Measure the output voltage of the batteries and voltage across each bulb.  What is the power consumed by each?  How does this compare with the powers you determined in A(3)?

Initial Sign-off __________

C.            Light Bulbs in Parallel

The goal is to determine whether the total current equals the sum of the currents in the branches.

1.         Connect an A and a B in parallel with the batteries.  Measure the output voltage of the batteries and the voltage across each bulb.  Is what you measured consistent with what you know/expect about parallel circuits?  Explain.  Also explain any inconsistencies with theory.

2.         If a single A bulb is connected to the batteries, how does its brightness compare with an A and a B in parallel?  Try it by connecting an A and then “switching” on a B.  Explain why what you notice is to be expected.

3.            With an A and a B in parallel,

a)            Measure the current through each bulb and the voltage across each.

b)            What is the total current (add the currents from the two loops together) and battery output voltage;

c)            Using the resistances determined in A(1) of the two bulbs, use Ohm’s law to calculate what the total current and current through each bulb “should be” in parallel, and compare this to what was measured in parts (a) and (b).  Explain any differences.

Initial Sign-off __________ ]]> http://hildebrandb.edublogs.org/2010/04/26/laboratory-8-dc-circuits/feed/ 1 http://hildebrandb.edublogs.org/2010/03/31/outlook-fluids/ http://hildebrandb.edublogs.org/2010/03/31/outlook-fluids/#comments Wed, 31 Mar 2010 12:44:12 +0000 hildebrandb http://hildebrandb.edublogs.org/?p=340 Mar 1 – Introduction to Fluids

Mar 2 – 5X, Continue with Fluids

Mar 3 – 3X, Continue with Fluids

Mar 4 – Thermodynamics

Mar 5 – Finish thermo, Happy Spring Break!

No quiz/test given on this material.

The theoretical equation T = 2π sqroot (L/g) describes how the period T of a pendulum (the round trip time) depends on its length L and the acceleration due to gravity g.

1. The theoretical equation is an approximation, as all derivations rely on various assumptions.  Determine experimentally whether T depends on

a. the initial angle or amplitude;

b. the mass of the bob.

Explain clearly what you did.

2. Verify that the above equation has consistent units.  L is measured from where the string is clamped to the center of the “bob”.

3. For each of at least 10 different lengths, using about the same initial (small) angle, carefully measure T with a stopwatch.  Why should you time at least 10 consecutive periods (and then divide by the number you timed) instead of measuring a single period 10 times?

4. Use the appropriate regression to find an experimental relationship between T and L.  Is your result consistent with the theoretical equation? Explain.

5. Assuming that you answered “yes” to the question in (3), use the result of (3) and the theoretical equation to calculate g and a % error.  Explain clearly what you did.  Do NOT simply plug various values of T and L into the theoretical equation and average the g’s.

6. Explain the sixth panel in the cartoon on your handout.  Better yet, apply it to your data and see what happens…

Due Date: Thursday, February 11

Feb 5: 3X, Start rotational motion

Feb 8: Rotational motion – centripetal acceleration/force

Feb 9: Rotational motion – problems, demonstration

Feb 10 : X

Feb 11: Homework due, Gravitational Force

Feb 12: Gravitational Force, Start Torque

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Feb 15 – Presidents Day – No School

Feb 16 – Finish gravitational force, Torque

Feb 17 – Torque Lab

Feb 18 – Torque Lab continued

Feb 19 – 3X, Work on Problem set (See below)

Homework: Due Tuesday, Feb 23

Chapter 9: A2, A5            Chapter 13: C 2, 1.2, 2.1, 2.2, 2.4, 10.1, 10.3                     Chapter 11: 1.1, 1.2, 1.3

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Feb 22 -Finish Torque lab, work on homework.

Feb 23 – Homework Due, Review for Rotational Motion Test

Feb 24 – X, I will have graded homework that you can pick up.

Feb 25 – Rotational Motion Test

Feb 26 – Fun with Angular momentum!

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