Electricity and Magnetism Answers

Enrichment Activity 2. Beam Me a Light

In this activity you will be needing:

Flashlight

Red, blue, and green construction paper

See-through colored cellophane

Masking tape or a rubber band

Research Questions

1. Why did the papers look white, red, blue, and green (respectively) in white light?

2. How did the construction and cellophane affect the white flashlight beam?

3. Why did the yellow and green papers seem to lose their color when red light was

shined on them?

Procedure

1. Darken the room as much as possible.

2. Turn on the flashlight and aim it at the white paper. Observe and record the

color of the paper in the data table,​

Question:

1. Why did papers look white, red, blue, and green (respectively) in white light?

2. How did the construction and cellophane affect the white flashlight beam?

3. Why did the yellow and green papers seem to lose their color when red light is shined on them?

Enrichment Activity 2. Beam Me a Light

In this activity you will be needing:

Flashlight

Red, blue, and green construction paper

See-through colored cellophane

Masking tape or a rubber band

Research Questions

1. Why did the papers look white, red, blue, and green (respectively) in white light?

2. How did the construction and cellophane affect the white flashlight beam?

3. Why did the yellow and green papers seem to lose their color when red light was

shined on them?

Procedure

1. Darken the room as much as possible.

2. Turn on the flashlight and aim it at the white paper. Observe and record the

color of the paper in the data table,​

Question:

1. Why did papers look white, red, blue, and green (respectively) in white light?

2. How did the construction and cellophane affect the white flashlight beam?

3. Why did the yellow and green papers seem to lose their color when red lights was shined on them?

In the ground state of the hydrogen atom the electron describe a circular orbit of radius 5.3×10^-11m at a speed 2.2×10^6ms^-1(a) what is the average electric current resulting from the electron movement (b) calculate the value of B established by the electron at the nuclues

A rectangular loop of wire with sides H = 26 cm and W - 50 cm is located in a region containing a constant magnetic field

B - 0.87 T that is aligned with the positive y-axis as shown. The loop carries current I = 387 mA. The plane of the loop is

inclined at an angle 8 - 33° with respect to the x-axis.

1) What is My the x-component of the magnetic moment vector of the loop?

2) What is My, the y-component of the magnetic moment vector of the loop?

3) What is Ty, the z-component of the torque exerted on the loop?

4) What is Fpc, the magnitude of the force exerted on segment bc of the loop?.

5) What is the direction of the force that is exerted on the segment be of the loop?

An electric current is flowing in a circular wire of radius a. At What distance from the centre on the axis of the circular wire will the magnetic field be 1/8th of it's value at the centre

Six identical charges each of charge 2 c are placed at the corner of a cude of side 0.2m .compute the energy of the system

3. (a) Calculate the energy stored in a solenoid of self-inductance 0.1 H when a steady current of 1A is flowing through it? (5)

(b) What is the reason that a self-inductance cannot store energy for long periods of time. (5)

4. Two long parallel wires are separated by 100 cm, and each carry 1 A current in the same direction. Calculate the force between the wires per unit length. (µ_o = 1.26x10^-6Wb A^-1 m^-2) [10]

. (a) Calculate the self-inductance of a toroidal coil consisting of 1000 turns of wire, each of radius 1 cm wound uniformly on a non-ferromagnetic ring of mean radius 10 cm. (10)

(b) A circuit containing an air-cored solenoid of self-inductance 0.1 H carries a steady current of 1 A. A switch in the circuit is opened, reducing the current to zero in a time of 1 ms. Determine the magnitude of the induced emf across the solenoid, assuming the current fallsto zero at a constant rate.

1. A toroidal sample of magnetic material of susceptibility x = 2 × 10^-2 is wound with 100 turns of wire carrying a current of 2 A. The toroid is 0.10 m long.

(a) Find the solenoidal current density.(3)

(b) Determine the magnetic field intensity H produced by the current.(3)

(c) Calculate μ, the magnetic permeability of the material.(3)

(d) Calculate the induced magnetization M in the material.(3)

(e) Calculate the magnetic field B resulting from the current and the magnetization of the material.(3)

An electric potential field is produced by point charges 1 mC and 4 mC located at (-2,1,5) and (1,3,-1) respectively. The energy stored in the field is