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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

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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?

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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"} {}

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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?

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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"} {}

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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?

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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} {}

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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?

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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.

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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} {}

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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?

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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} {}

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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.

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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

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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?

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Questions & Answers

how do you calculate the 5% uncertainty of 4cm?
melia Reply
4cm/100×5= 0.2cm
haider
how do you calculate the 5% absolute uncertainty of a 200g mass?
melia Reply
= 200g±(5%)10g
haider
use the 10g as the uncertainty?
melia
which topic u discussing about?
haider
topic of question?
haider
the relationship between the applied force and the deflection
melia
sorry wrong question i meant the 5% uncertainty of 4cm?
melia
its 0.2 cm or 2mm
haider
thank you
melia
Hello group...
Chioma
hi
haider
well hello there
sean
hi
Noks
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
To use the vocabulary of model theory and meta-logic, a theory is a set of sentences which can be derived from a formal model using some rule of inference (usually just modus ponens). So, for example, Number Theory is the set of sentences true about numbers. But the model is a structure together wit
Jesilda
with an iterpretation.
Jesilda
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

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Source:  OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
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