Physics 2 Lab

The SI units for electrical field are?

V/m

If the electric field sketched around a charge, Q, is oriented as shown by the arrows in the sketch below, Q could be:

an electron

How is the magnitude of the electric field represented by a graphic description with electric field lines?

the electric field intensity is greater where there are more lines per area

If at some point along the straight line directly between two charges the strength of the electric field at that point is found to be zero what can we say for sure about those two charges?

The charges must be like charges (both positive or both negative).

The local direction of an electric field line, at any point, is said to be tangent to the field line at that point.

True

What are the SI units for resistance?

Ohms (Ω)

A material is said to be ohmic if which of the following is true?

If it has a constant resistance for a wide range of voltages.

In this lab (Ohm's Law) we are going to make a Voltage v.s. Current graph. The slope of this graph will represent what?

R (The resistance of the material).

Which of the following relationship gives the resistance of a material?

V/i

What is the theoretical resistance of the resistor used in the first part of today's lab?

100 ohms.

What is the equivalent resistance of the three resistors connected as shown in the diagram to the right, when the resistance of the resistors are as given: R1 = 25 ohms, R2 = 50 ohms, R3 = 100 ohms.

175 ohms

What is always true about resistors connected in parallel?

There is the same potential difference across each of them.

What is always true about resistors connected in series?

They each have the same current passing through them.

What is the SI unit for current?

Amps

In today's lab (Simple Electrical Circuits) we will be using a voltage sensor to measure the voltage over our resistors, and a current sensor to measure the current going through our resistors. Each of these sensors need to be connected to the resistor in a particular way in order to work correctly. Which of the following are the correct ways?

Voltage sensor connected in parallel. Current sensor connected in series.

Which of the following is true regarding the Junction Rule?

The sum of all currents entering a junction in a circuit equals the sum of all currents leaving the junction.

Kirchhoff's Rules can be used to analyze a complex circuit when the formulas for resistors in parallel, or in series becomes impractical, or even impossible to use.

True.

What is the loop rule?

The net change in potential around any closed path in a circuit is zero.

When measuring the voltage going over a particular circuit component the voltmeter (volt sensor) must be connected to that circuit component how?

Always in parallel with that component.

When measuring the current going over a particular circuit component the Ammeter (current sensor) must be connected to that circuit component how?

Always in series with that component.

Which of the following algebraic expressions is equal to the Time Constant of a RC Circuit?

RC.

The "RC" in a RC circuit stands for what?

resistor and capacitor

What is the Time Constant of an RC circuit?

The time it takes for a fully discharged capacitor to be charged to 63.2% of its maximum value.

Resonant frequency is?

When the natural frequency is equal to the forced frequency

For an LRC circuit at resonance, the reactance of the inductor and the capacitor cancel each other so that the impedance is equal to the resistance.

True.

According to the handout what are the three main factors that affect the resistance of a device?

Length, cross-section area, type of material.

The SI units of Resistivity are?

Ωm

How does the cross-section of the material affect its resistance?

The bigger the cross-section the smaller the resistance.

In the lab Resistance and Resistivity lab we will be experimentally confirming the resistivity of what material?

Brass.

How many graphs did you make in the Resistance and Resistivity lab?

4.

A changing magnetic flux in the presence of a conductor induces a voltage in the conductor.

True.

The more turns of wire in a coil, the smaller the magnitude of an EMF is produced.

False.

The area under a voltage v.s. time graph represents? Should those two areas be equal?

The change in magnetic flux; yes.

What is the foam pad used for?

Cushion the magnet so it doesn't strike the floor and break.

The induced _____ is proportional to the number of loops, or coils, of the wire and the rate at which the magnetic flux changes inside the loops of wire.

EMF.

The Law of Reflection says that the angle of incidences is always greater than the angle of reflection.

False.

When light moves from one medium into another medium the speed of light changes. This phenomenon is called refraction.

True.

Assume the speed of light in a particular medium is v=2x10^8 m/s, and given that the speed of light in the vacuum is c=3x10^8 m/s, then the value of the index of refraction for this medium is?

1.5.

Assume a beam of light hits the boundary separating medium 1, with index of refraction n1 and medium 2, with index of refraction n2. If total internal reflection occurs at the boundary that separates medium 1 and medium 2, then we know which of the following?

n1>n2.

The index of refraction can be less than 1 for normal materials.

False.

The magnifications M of spherical mirrors is described by which of the following equations?

M = -q/p

The Principle Axis of a circular mirror goes through the center of the mirror.

True.

In relations to the center of curvature of the mirror, where is the mirror's focal point?

Halfway between the center of the curvature and the mirror.

For a Concave mirror the reflective side of the mirror is on what side of the curved surface?

On the inside of the curved surface.

In today's experiment, initially how far away from the light source are you to place the mirror?

100 cm.

The magnifications M of spherical thin lenses are described by which of the following equations?

M = -q/p.

A thin converging lens takes the rays of light that are parallel and:

Converges them to a common point.

What happens as your object distance increases?

The image distance will get closer and closer in value to focal length of the lens.

In ray tracing there are three rays that are used. Which ray travels through the center of the lens?

The Chief Ray.

The object distance is measured from the lens to the observer.

False.

Electric charge is

one fundamental property of matter.

How does an object become electrostatically charged?

When electrons are transferred.

A coulomb is a unit of electrical

charge.

A quantity of electrical charge is measured in a unit called a (an)

coulomb.

Which of the following is most likely to acquire an electrostatic charge?

objects that are electrical nonconductors.