Please Fill in the Blanks and Answer the Short Questions/Problems When Appropriate s1

Leader: German Parada Dead Week Unit 2 review Course: Phys 222 Supplemental Instruction Instructor: Dr. Soeren Prell Iowa State University Date: 4/29/2014 Please fill in the blanks and answer the short questions/problems when appropriate.

Current is defined as the amount of _____ per _____, and its unit is ______. A related quantity, the ______, is defined as current per area. This quantity can be related to microscopic movement of electrons by this equation, Current flows through any object due to a ______across the object, also referred to as ______. The ratio of voltage to current is referred as ______, with units of _____. This relationship is known as ______, as follows, For a wire, the resistance is a factor of the dimensions and the resistivity, as follows Both resistivity and resistance are affected by ______changes.

When several resistors are connected in series, the equivalent resistance can be found using the following equation . If they are connected in ______, the equation to use is . These equations can be used to simplify circuits.

The _____ dissipated/provided by a circuit element refers to the amount of energy used per unit time. This quantity is calculated by multiplying the ______times the ______, or using similar equations involving resistance. The equations are

To find current or voltages in simple circuits, find the ______resistance and use _____ Law. However, if the circuits are more complicated, resistances can be neither in ______nor in ______. Then, the two ______circuit rules can be used. The ______Rule states that the ______currents at a junction must equal the ______. The ______Rule states that the ______of ______around a ______must equal _____.

a. A wire must be replaced by another wire of the same length but material with 3 times the original resistivity. If the resistance is to be halved, what should the radius of this wire be?

b. The switch has been open for a long time. What would happen to the brightness of both bulbs when the switch is closed? Both bulbs are identical, and the resistance has half the resistance of the bulbs.

c. The power dissipated by a 5.5Ω resistor when connected to a 9V battery is only 10W. What is the internal resistance of the battery?

A particle will experience magnetic force if it has _____ and ______, and the ______and magnetic field are not ______. This is because the magnetic force is a ______product, which follows the ______rule. To use this rule, the thumb is placed along the ______; the index finger points along the ______; and the ______finger points along the force. To find the numerical value of the magnetic force, the following equation is used If a particle enters a region with ______field, it will describe a circle with constant ______, as given by the following equation

Supplemental Instruction 1060 Hixson-Lied Student Success Center v 294-6624 v www.si.iastate.edu A wire carrying ______also will experience a magnetic force, as ______is composed of moving electrons. The expression for this force is , another vector product. And if the wire makes a closed loop, the loop will have a magnetic ______, which is the product of the ______and the current. To find the direction of this vector, the “thumb” rule can be used, in which the ______are curled in the direction of the ______and the thumb points along the ______vector. The ______experienced by this loop in a magnetic field is given by this equation . The _____ is maximum if the loop and the B-field are ______, and it is minimum when they are ______. Additionally, the ______of this system can be found by calculating the negative ______product of the ______and the B-field.

______charges generate magnetic field, as described by the ______Law, as follows . If a current generates a magnetic field, a modified version can be used . The ______Rule can be used to find the ______of the B-field at any given point, of the “Thumb” Rule can also be applied. After ______, the expressions below describe the B-field generated by different geometries Configuration Straight Wire Ring of current, Ring of current, Solenoid above plane on the plane B-field

The direction of the B-field for these geometries can be found using the “Thumb” Rule. For a straight wire, the thumb points along ______while the fingers indicate the ______. On the other hand, for the rings, the fingers curl around the ______while the thumb indicates the ______. When two wires with current are placed parallel to each other, the wires will ______if the currents are going in the same direction and will ______if the currents are going in ______directions. A generalized way to calculate B-fields is called ______Law, which states that the ____ integral of B*dl equals the net ______current times the vacuum ______.

a. An electron is travelling next to a wire carrying current I1 along the positive y-axis. If the velocity of the electron, v, is parallel to the current direction, find the magnitude and direction of the magnetic force on the electron.

b. A ring of wire of radius r1 carried a current CCW, while a smaller ring with radius r2 lies concentrically inside the first ring and carries a current twice as large, this time in the CW direction. Determine the direction and magnitude of the B-field in the center of both rings.

c. An isosceles wire triangle with its height twice as large as its base lays on a table carrying current in the CCW direction. If there is a magnetic field going into the table, what is the direction of the net force on the triangle?

A strange phenomenon occurs when the magnetic _____ across a loop changes as a function of _____. This is called ______, and it follows ______Law, as follows

The ______created tries to induce a ______that will ______the original change in ______, a statement known as ______. There are three common ways of changing the flux through a loop: Increasing/Decreasing the ______going through the loop, ______the loop into or out of a region of magnetic field, and ______the loop with existing magnetic field. It is necessary to determine whether the magnetic flux is ______or ______, and then use the “Thumb” rule to determine the ______of the current that ______the change. Then, Faraday’s Law can be used to determine the ______of the ______created – then, ______Law can be used to determine the ______.

a. Determine the force required to pull a square ring of wire (side L) from a region of magnetic field B at a constant velocity v.

b. A thin metal ring is placed around a thick wire which carries a current going out of the plane when watched from above. The ring and the wire are concentric. If such current is decreasing, in which direction will the current in the wire be pointing?

c. A circular wire with radius r=7cm and resistance 15Ω lies vertically inside a uniform but time-changing B-field pointing out of the plane of the ring. If the field increases from 1.0T to 3.5T in 0.03s, determine the direction and magnitude of the current in the ring.

When two loops are next to each other, a change in the _____ in one of them will ______an ______on the other one. This process is described by the following equation where M is called ______, with units of ____and can be calculated from

Some circuit elements called ______exhibit a similar behavior, called ______. The expression relating the change in _____ with the EMF created is , where L is the ______, with units of ____. For a solenoid, the expression for L is The negative sign of the equation indicates that the ______current will try to ______the change in current, and that the ______induced will point accordingly. Inductors also store ______, as shown in the following equation . The energy is actually stored in the ______, as described by

a. Two solenoids with the same cross-sectional area have identical inductance, but one of them is half as large as the other. Determine the ratio of the total number of turns of the long solenoid to the short solenoid.