Magnetic Fields
Induced Currents and Magnetic Flux
Electromagnetic Waves
Random
Chapter 24 Conceptual Questions
100
An electron moving at 4.00×103m/s4.00×103m/s in a 1.25-T magnetic field experiences a magnetic force of 1.40×10−16N1.40×10−16N. What angle does the velocity of the electron make with the magnetic field
10o
100
True or False: A conducting loop of wire can create an induced Emf in a constant magnetic field
False
Emf = Δ Flux / Δ time
100
What is the maximum electric field strength in an electromagnetic wave that has a maximum magnetic field strength of 5.00×10^−4T?
1.5 x 105 V/m
100
How would you calculate the magnitude of a magnetic field created by a circular loop of wire? A straight length of wire?
length of wire - B = µ0I/2πr
loop of wire - B = Nµ0I/2R
100
Within an electromagnetic wave, the magnetic field and electric field are situated ... to one another
perpendicular (90 degrees)
200
The geographic North Pole corresponds with the ... pole of a magnet while the geographic South Pole corresponds with the ... pole of a magnet
North Pole = South pole of a magnet
South Pole = North pole of a magnet
200
What is the equation to determine the amount of magnetic flux passing through a given point in space?
Magnetic Flux = B x A x cos θ
(where θ is the angle between the magnetic field and normal)
200
Two microwave frequencies are authorized for use in microwave ovens: 900 and 2560 MHz. Calculate the wavelength of each.
0.333 m
0.117 m
200
Unpolarized light with an intensity of S0 has passed through one single polarizer. How would you solve for the intensity of the light after it has passed through this polarizer?
S1 = 1/2 S0
300
What is the direction of the current flowing in the following coils?
(a) clockwise
(b) clockwise
(c) counter clockwise
300
A negatively charged particle moves downward as it is acted on by a force due to a magnetic field. This force vector faces out of the page. What is the direction of the magnetic field experienced by this particle?
To the left
300
As a sound source moves towards an observer, the frequency of the sound .... while as the source moves away from the observer, the frequency of the sound ...
increases as source moves closer
decreases as source moves away
400
(a) \\\A physicist performing a sensitive measurement wants to limit the magnetic force on a moving charge in her equipment to less than 1.00×10^−12N. What is the greatest the charge can be if it moves at a maximum speed of 30.0 m/s in the Earth’s field (5 x 10-5 T)?
6.7×10^−10 C
400
A 0.250 m radius, 500-turn coil is rotated one-fourth of a revolution in 4.17 ms, originally having its plane perpendicular to a uniform magnetic field. (This is 60 rev/s.) Find the magnetic field strength needed to induce an average emf of 10,000 V.
0.425 T
400
Assume the helium-neon lasers commonly used in student physics laboratories have power outputs of 0.250 mW. (a) Find the peak magnetic field strength. (b) Find the peak electric field strength.
B = 1.63 x 10-6 T
E = 490 N/C
400
A 2.50-m segment of wire supplying current to the motor of a submerged submarine carries 1000 A and feels a 4.00-N repulsive force from a parallel wire 5.00 cm away. What is magnitude of the current in the other wire?
400 Amps
500
Calculate the magnetic field strength needed on a 200-turn square loop 20.0 cm on a side to create a maximum torque of 300 N⋅m if the loop is carrying 25.0 A.
B = 1.51 T
500
Suppose a 50-turn coil lies in the plane of the page in a uniform magnetic field that is directed into the page. The coil originally has an area of 0.250 m2. It is stretched to have no area in 0.100 s. What is the direction and magnitude of the induced emf if the uniform magnetic field has a strength of 1.50 T?
188 V in the clockwise direction
500
During normal beating, the heart creates a maximum 4.00-mV potential across 0.300 m of a person’s chest, creating a 1.00-Hz electromagnetic wave. (a) What is the maximum electric field strength created? (b) What is the corresponding maximum magnetic field strength in the electromagnetic wave? (c) What is the wavelength of the electromagnetic wave?
E = 1.33 x 10-2 V/m or N/C
B = 4.45 x 10-11 T
λ = 3 x 108 m
500
What are the 7 types of electromagnetic waves that we learned about in this course? Order them from lowest to highest energy. Between what wavelgenths does visible light occur?
Radio and TV waves
Microwaves
Infrared light
Visible light (400-700 nm)
Ultraviolet
X-rays
Gamma rays