<< Chapter < Page Chapter >> Page >

Problems&Exercises

Integrated Concepts

The 54.0-eV electron in [link] has a 0.167-nm wavelength. If such electrons are passed through a double slit and have their first maximum at an angle of 25 . size 12{"25" "." 0°} {} , what is the slit separation d size 12{d} {} ?

0.395 nm

Got questions? Get instant answers now!

Integrated Concepts

An electron microscope produces electrons with a 2.00-pm wavelength. If these are passed through a 1.00-nm single slit, at what angle will the first diffraction minimum be found?

Got questions? Get instant answers now!

Integrated Concepts

A certain heat lamp emits 200 W of mostly IR radiation averaging 1500 nm in wavelength. (a) What is the average photon energy in joules? (b) How many of these photons are required to increase the temperature of a person’s shoulder by 2 . C size 12{2 "." 0°C} {} , assuming the affected mass is 4.0 kg with a specific heat of 0 .83 kcal /kg ºC size 12{0 "." "83"" kcal/kg" cdot °C} {} . Also assume no other significant heat transfer. (c) How long does this take?

(a) 1.3 × 10 19 J size 12{1 "." "33" times "10" rSup { size 8{ - "19"} } " J"} {}

(b) 2 . 1 × 10 23 size 12{2 "." 1 times "10" rSup { size 8{"23"} } } {}

(c) 1 . 4 × 10 2 s size 12{1 "." 4 times "10" rSup { size 8{2} } " s"} {}

Got questions? Get instant answers now!

Integrated Concepts

On its high power setting, a microwave oven produces 900 W of 2560 MHz microwaves. (a) How many photons per second is this? (b) How many photons are required to increase the temperature of a 0.500-kg mass of pasta by 45 . C size 12{"45" "." 0°C} {} , assuming a specific heat of 0 . 900 kcal/kg ºC size 12{0 "." "900"" kcal/kg" cdot °C} {} ? Neglect all other heat transfer. (c) How long must the microwave operator wait for their pasta to be ready?

Got questions? Get instant answers now!

Integrated Concepts

(a) Calculate the amount of microwave energy in joules needed to raise the temperature of 1.00 kg of soup from 20 . C size 12{"20" "." 0°C} {} to 100 ºC size 12{"100"°C} {} . (b) What is the total momentum of all the microwave photons it takes to do this? (c) Calculate the velocity of a 1.00-kg mass with the same momentum. (d) What is the kinetic energy of this mass?

(a) 3 . 35 × 10 5 J size 12{3 "." "35" times "10" rSup { size 8{5} } " J"} {}

(b) 1 . 12 × 10 –3 kg m/s size 12{1 "." "12" times "10" rSup { size 8{"–3"} } " kg" cdot "m/s"} {}

(c) 1 . 12 × 10 –3 m/s size 12{1 "." "12" times "10" rSup { size 8{"–3"} } " m/s"} {}

(d) 6.23 × 10 –7 J size 12{6 "." "23" times "10" rSup { size 8{"–7"} } " J"} {}

Got questions? Get instant answers now!

Integrated Concepts

(a) What is γ size 12{γ} {} for an electron emerging from the Stanford Linear Accelerator with a total energy of 50.0 GeV? (b) Find its momentum. (c) What is the electron’s wavelength?

Got questions? Get instant answers now!

Integrated Concepts

(a) What is γ size 12{γ} {} for a proton having an energy of 1.00 TeV, produced by the Fermilab accelerator? (b) Find its momentum. (c) What is the proton’s wavelength?

(a) 1 . 06 × 10 3 size 12{1 "." "07" times "10" rSup { size 8{3} } } {}

(b) 5 . 33 × 10 16 kg m/s size 12{5 "." "34" times "10" rSup { size 8{ - "16"} } `"kg" cdot "m/s"} {}

(c) 1 . 24 × 10 18 m size 12{1 "." "24" times "10" rSup { size 8{ - "18"} } `m} {}

Got questions? Get instant answers now!

Integrated Concepts

An electron microscope passes 1.00-pm-wavelength electrons through a circular aperture 2 . 00 μm size 12{2 "." "00 μm"} {} in diameter. What is the angle between two just-resolvable point sources for this microscope?

Got questions? Get instant answers now!

Integrated Concepts

(a) Calculate the velocity of electrons that form the same pattern as 450-nm light when passed through a double slit. (b) Calculate the kinetic energy of each and compare them. (c) Would either be easier to generate than the other? Explain.

(a) 1 . 62 × 10 3 m/s size 12{1 "." "62" times "10" rSup { size 8{3} } " m/s"} {}

(b) 4 . 42 × 10 19 J size 12{4 "." "41" times "10" rSup { size 8{ - "19"} } " J"} {} for photon, 1 . 19 × 10 24 J size 12{1 "." "19" times "10" rSup { size 8{ - "24"} } `J} {} for electron, photon energy is 3 . 71 × 10 5 size 12{3 "." "71" times "10" rSup { size 8{5} } } {} times greater

(c) The light is easier to make because 450-nm light is blue light and therefore easy to make. Creating electrons with 7.43 μeV size 12{7 "." "43"`"μeV"} {} of energy would not be difficult, but would require a vacuum.

Got questions? Get instant answers now!

Integrated Concepts

(a) What is the separation between double slits that produces a second-order minimum at 45 . size 12{"45" "." 0°} {} for 650-nm light? (b) What slit separation is needed to produce the same pattern for 1.00-keV protons.

(a) 2 . 30 × 10 6 m size 12{2 "." "30" times "10" rSup { size 8{ - 6} } " m"} {}

(b) 3 . 20 × 10 12 m size 12{3 "." "20" times "10" rSup { size 8{ - "12"} } `m} {}

Got questions? Get instant answers now!

Integrated Concepts

A laser with a power output of 2.00 mW at a wavelength of 400 nm is projected onto calcium metal. (a) How many electrons per second are ejected? (b) What power is carried away by the electrons, given that the binding energy is 2.71 eV? (c) Calculate the current of ejected electrons. (d) If the photoelectric material is electrically insulated and acts like a 2.00-pF capacitor, how long will current flow before the capacitor voltage stops it?

Got questions? Get instant answers now!

Integrated Concepts

One problem with x rays is that they are not sensed. Calculate the temperature increase of a researcher exposed in a few seconds to a nearly fatal accidental dose of x rays under the following conditions. The energy of the x-ray photons is 200 keV, and 4 . 00 × 10 13 size 12{4 "." "00" times "10" rSup { size 8{"13"} } } {} of them are absorbed per kilogram of tissue, the specific heat of which is 0 . 830 kcal/kg ºC size 12{0 "." "830"" kcal/kg" cdot °C} {} . (Note that medical diagnostic x-ray machines cannot produce an intensity this great.)

3 . 69 × 10 4 ºC size 12{3 "." "69" times "10" rSup { size 8{ - 4} } `°C} {}

Got questions? Get instant answers now!

Integrated Concepts

A 1.00-fm photon has a wavelength short enough to detect some information about nuclei. (a) What is the photon momentum? (b) What is its energy in joules and MeV? (c) What is the (relativistic) velocity of an electron with the same momentum? (d) Calculate the electron’s kinetic energy.

Got questions? Get instant answers now!

Integrated Concepts

The momentum of light is exactly reversed when reflected straight back from a mirror, assuming negligible recoil of the mirror. Thus the change in momentum is twice the photon momentum. Suppose light of intensity 1 . 00 kW/m 2 size 12{1 "." "00 kW/m" rSup { size 8{2} } } {} reflects from a mirror of area 2 . 00 m 2 size 12{2 "." "00 m" rSup { size 8{2} } } {} . (a) Calculate the energy reflected in 1.00 s. (b) What is the momentum imparted to the mirror? (c) Using the most general form of Newton’s second law, what is the force on the mirror? (d) Does the assumption of no mirror recoil seem reasonable?

(a) 2.00 kJ

(b) 1 . 33 × 10 5 kg m/s size 12{1 "." "33" times "10" rSup { size 8{ - 5} } `"kg" cdot "m/s"} {}

(c) 1 . 33 × 10 5 N size 12{1 "." "33" times "10" rSup { size 8{ - 5} } " N"} {}

(d) yes

Got questions? Get instant answers now!

Integrated Concepts

Sunlight above the Earth’s atmosphere has an intensity of 1 . 30 kW/m 2 size 12{1 "." "30"" kW/m" rSup { size 8{2} } } {} . If this is reflected straight back from a mirror that has only a small recoil, the light’s momentum is exactly reversed, giving the mirror twice the incident momentum. (a) Calculate the force per square meter of mirror. (b) Very low mass mirrors can be constructed in the near weightlessness of space, and attached to a spaceship to sail it. Once done, the average mass per square meter of the spaceship is 0.100 kg. Find the acceleration of the spaceship if all other forces are balanced. (c) How fast is it moving 24 hours later?

Got questions? Get instant answers now!

Questions & Answers

Calculate the work done by an 85.0-kg man who pushes a crate 4.00 m up along a ramp that makes an angle of 20.0º20.0º with the horizontal. (See [link] .) He exerts a force of 500 N on the crate parallel to the ramp and moves at a constant speed. Be certain to include the work he does on the crate an
Collins Reply
What is thermal heat all about
Abel Reply
why uniform circular motion is called a periodic motion?.
Boniface Reply
when a train start from A & it returns at same station A . what is its acceleration?
Mwdan Reply
what is distance of A to B of the stations and what is the time taken to reach B from A
BELLO
the information provided is not enough
aliyu
Hmmmm maybe the question is logical
yusuf
where are the parameters for calculation
HENRY
there is enough information to calculate an AVERAGE acceleration
Kwok
mistake, there is enough information to calculate an average velocity
Kwok
~\
Abel
what is the unit of momentum
Abel
wha are the types of radioactivity ?
Worku Reply
what are the types of radioactivity
Worku
what is static friction
Golu Reply
It is the opposite of kinetic friction
Mark
static fiction is friction between two surfaces in contact an none of sliding over on another, while Kinetic friction is friction between sliding surfaces in contact.
MINDERIUM
I don't get it,if it's static then there will be no friction.
author
It means that static friction is that friction that most be overcome before a body can move
kingsley
static friction is a force that keeps an object from moving, and it's the opposite of kinetic friction.
author
It is a force a body must overcome in order for the body to move.
Eboh
If a particle accelerator explodes what happens
Eboh
why we see the edge effect in case of the field lines of capacitor?
Arnab
what is wave
Muhammed Reply
what is force
Muhammed
force is something which is responsible for the object to change its position
MINDERIUM
more technically it is the product of mass of an object and Acceleration produced in it
MINDERIUM
wave is disturbance in any medium
iqra
energy is distributed in any medium through particles of medium.
iqra
If a particle accelerator explodes what happens
Eboh Reply
we have to first figure out .... wats a particle accelerator first
Teh
What is surface tension
Subi Reply
The resistive force of surface.
iqra
Who can tutor me on simple harmonic motion
yusuf Reply
on both a string and peldulum?
Anya
spring*
Anya
Yea
yusuf
Do you have a chit-chat contact
yusuf
I dont have social media but i do have an email?
Anya
Which is
yusuf
Where are you chatting from
yusuf
I don't understand the basics of this group
Jimmy
teach him SHM init
Anya
Simple harmonic motion
yusuf
how.an.equipotential.line is two dimension and equipotential surface is three dimension ?
syed Reply
definition of mass of conversion
umezurike Reply
Force equals mass time acceleration. Weight is a force and it can replace force in the equation. The acceleration would be gravity, which is an acceleration. To change from weight to mass divide by gravity (9.8 m/s^2).
Marisa
how many subject is in physics
Adeshina Reply
the write question should be " How many Topics are in O- Level Physics, or other branches of physics.
effiom
how many topic are in physics
Praise
Praise what level are you
yusuf
If u are doing a levels in your first year you do AS topics therefore you do 5 big topic i.e particles radiation, waves and optics, mechanics,materials, electricity. After that you do A level topics like Specific Harmonic motion circular motion astrophysics depends really
Anya
Yeah basics of physics prin8
yusuf
Heat nd Co for a level
yusuf
yh I need someone to explain something im tryna solve . I'll send the question if u down for it
Tamdy Reply
a ripple tank experiment a vibrating plane is used to generate wrinkles in the water .if the distance between two successive point is 3.5cm and the wave travel a distance of 31.5cm find the frequency of the vibration
Tamdy
hallow
Boniface
please send the answer
Boniface
the range of objects and phenomena studied in physics is
Bethel Reply
I don't know please give the answer
Boniface

Get the best College physics course in your pocket!





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