<< Chapter < Page Chapter >> Page >

Give an example of energy carried by an electromagnetic wave.

Got questions? Get instant answers now!

In an MRI scan, a higher magnetic field requires higher frequency radio waves to resonate with the nuclear type whose density and location is being imaged. What effect does going to a larger magnetic field have on the most efficient antenna to broadcast those radio waves? Does it favor a smaller or larger antenna?

Got questions? Get instant answers now!

Laser vision correction often uses an excimer laser that produces 193-nm electromagnetic radiation. This wavelength is extremely strongly absorbed by the cornea and ablates it in a manner that reshapes the cornea to correct vision defects. Explain how the strong absorption helps concentrate the energy in a thin layer and thus give greater accuracy in shaping the cornea. Also explain how this strong absorption limits damage to the lens and retina of the eye.

Got questions? Get instant answers now!

Problems&Exercises

(a) Two microwave frequencies are authorized for use in microwave ovens: 900 and 2560 MHz. Calculate the wavelength of each. (b) Which frequency would produce smaller hot spots in foods due to interference effects?

(a) 33.3 cm (900 MHz) 11.7 cm (2560 MHz)

(b) The microwave oven with the smaller wavelength would produce smaller hot spots in foods, corresponding to the one with the frequency 2560 MHz.

Got questions? Get instant answers now!

(a) Calculate the range of wavelengths for AM radio given its frequency range is 540 to 1600 kHz. (b) Do the same for the FM frequency range of 88.0 to 108 MHz.

Got questions? Get instant answers now!

A radio station utilizes frequencies between commercial AM and FM. What is the frequency of a 11.12-m-wavelength channel?

26.96 MHz

Got questions? Get instant answers now!

Find the frequency range of visible light, given that it encompasses wavelengths from 380 to 760 nm.

Got questions? Get instant answers now!

Combing your hair leads to excess electrons on the comb. How fast would you have to move the comb up and down to produce red light?

5.0 × 10 14 Hz

Got questions? Get instant answers now!

Electromagnetic radiation having a 15 . 0 μ m size 12{"15" "." 0-mm} {} wavelength is classified as infrared radiation. What is its frequency?

Got questions? Get instant answers now!

Approximately what is the smallest detail observable with a microscope that uses ultraviolet light of frequency 1 . 20 × 10 15 Hz size 12{1 "." "20"´"10" rSup { size 8{"15"} } " Hz"} {} ?

λ = c f = 3 . 00 × 10 8 m/s 1 . 20 × 10 15 Hz = 2 . 50 × 10 7 m size 12{λ= { {c} over {f} } = { {3 "." "00"´"10" rSup { size 8{8} } " m/s"} over {1 "." "20"´"10" rSup { size 8{"15"} } " Hz"} } = {underline {2 "." "50"´"10" rSup { size 8{ +- 7} } " m"}} } {}

Got questions? Get instant answers now!

A radar used to detect the presence of aircraft receives a pulse that has reflected off an object 6 × 10 5 s size 12{6´"10" rSup { size 8{-5} } " s"} {} after it was transmitted. What is the distance from the radar station to the reflecting object?

Got questions? Get instant answers now!

Some radar systems detect the size and shape of objects such as aircraft and geological terrain. Approximately what is the smallest observable detail utilizing 500-MHz radar?

0.600 m

Got questions? Get instant answers now!

Determine the amount of time it takes for X-rays of frequency 3 × 10 18 Hz size 12{3´"10" rSup { size 8{"18"} } " Hz"} {} to travel (a) 1 mm and (b) 1 cm.

Got questions? Get instant answers now!

If you wish to detect details of the size of atoms (about 1 × 10 10 m size 12{1´"10" rSup { size 8{-"10"} } " m"} {} ) with electromagnetic radiation, it must have a wavelength of about this size. (a) What is its frequency? (b) What type of electromagnetic radiation might this be?

(a) f = c λ = 3 . 00 × 10 8 m/s 1 × 10 - 10 m = 3 × 10 18 Hz size 12{f= { {c} over {λ} } = { {3 "." "00"´"10" rSup { size 8{8} } " m/s"} over {1´"10" rSup { size 8{ +- "10"} } " m"} } = {underline {3´"10" rSup { size 8{"18"} } " Hz"}} } {}

(b) X-rays

Got questions? Get instant answers now!

If the Sun suddenly turned off, we would not know it until its light stopped coming. How long would that be, given that the Sun is 1 . 50 × 10 11 m size 12{1 "." "50"´"10" rSup { size 8{"11"} } " m"} {} away?

Got questions? Get instant answers now!

Distances in space are often quoted in units of light years, the distance light travels in one year. (a) How many meters is a light year? (b) How many meters is it to Andromeda, the nearest large galaxy, given that it is 2 . 00 × 10 6 size 12{2 "." "00"´"10" rSup { size 8{6} } } {} light years away? (c) The most distant galaxy yet discovered is 12 . 0 × 10 9 size 12{"12" "." 0´"10" rSup { size 8{9} } } {} light years away. How far is this in meters?

Got questions? Get instant answers now!

Questions & Answers

the meaning of phrase in physics
Chovwe Reply
is the meaning of phrase in physics
Chovwe
write an expression for a plane progressive wave moving from left to right along x axis and having amplitude 0.02m, frequency of 650Hz and speed if 680ms-¹
Gabriel Reply
how does a model differ from a theory
Friday Reply
what is vector quantity
Ridwan Reply
Vector quality have both direction and magnitude, such as Force, displacement, acceleration and etc.
Besmellah
Is the force attractive or repulsive between the hot and neutral lines hung from power poles? Why?
Jack Reply
what's electromagnetic induction
Chinaza Reply
electromagnetic induction is a process in which conductor is put in a particular position and magnetic field keeps varying.
Lukman
wow great
Salaudeen
what is mutual induction?
je
mutual induction can be define as the current flowing in one coil that induces a voltage in an adjacent coil.
Johnson
how to undergo polarization
Ajayi Reply
show that a particle moving under the influence of an attractive force mu/y³ towards the axis x. show that if it be projected from the point (0,k) with the component velocities U and V parallel to the axis of x and y, it will not strike the axis of x unless u>v²k² and distance uk²/√u-vk as origin
Gabriel Reply
show that a particle moving under the influence of an attractive force mu/y^3 towards the axis x. show that if it be projected from the point (0,k) with the component velocities U and V parallel to the axis of x and y, it will not strike the axis of x unless u>v^2k^2 and distance uk^2/√u-k as origin
Gabriel Reply
No idea.... Are you even sure this question exist?
Mavis
I can't even understand the question
Ademiye
yes it was an assignment question "^"represent raise to power pls
Gabriel
mu/y³ u>v²k² uk²/√u-vk please help me out
Gabriel
An engineer builds two simple pendula. Both are suspended from small wires secured to the ceiling of a room. Each pendulum hovers 2 cm above the floor. Pendulum 1 has a bob with a mass of 10kg . Pendulum 2 has a bob with a mass of 100 kg . Describe how the motion of the pendula will differ if the bobs are both displaced by 12º .
Imtiaz Reply
no ideas
Augstine
if u at an angle of 12 degrees their period will be same so as their velocity, that means they both move simultaneously since both both hovers at same length meaning they have the same length
Ademiye
Modern cars are made of materials that make them collapsible upon collision. Explain using physics concept (Force and impulse), how these car designs help with the safety of passengers.
Isaac Reply
calculate the force due to surface tension required to support a column liquid in a capillary tube 5mm. If the capillary tube is dipped into a beaker of water
Mildred Reply
find the time required for a train Half a Kilometre long to cross a bridge almost kilometre long racing at 100km/h
Ademiye
method of polarization
Ajayi
What is atomic number?
Makperr Reply
The number of protons in the nucleus of an atom
Deborah
type of thermodynamics
Yinka Reply
oxygen gas contained in a ccylinder of volume has a temp of 300k and pressure 2.5×10Nm
Taheer Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'College physics' conversation and receive update notifications?

Ask