Concept explainers
(a)
The amplitude of the electric field of the helium-neon laser.
(a)
Answer to Problem 38P
The amplitude of the electric field is
Explanation of Solution
The diameter of the beam of laser is
Write the formula for the energy of a single photon.
Here,
Write the formula for the power carried by the laser beam.
Here,
Write the formula for the average poynting vector.
Here,
Write the formula for the average poynting vector in terms of electric field.
Here,
Re-write the above equation to get an expression for
Conclusion:
Substitute
Substitute
Substitute
Substitute
The amplitude of the electric field is
(b)
The amplitude of the magnetic field of the helium-neon laser.
(b)
Answer to Problem 38P
The amplitude of the magnetic field is
Explanation of Solution
The diameter of the beam of laser is
Write the formula for the magnitude of the magnetic field.
Here,
Conclusion:
Substitute
The amplitude of the magnetic field is
(c)
The force exerted by the beam on a perfectly reflecting surface when it is incident perpendicularly.
(c)
Answer to Problem 38P
The force exerted on the perfectly reflecting surface is
Explanation of Solution
The diameter of the beam of laser is
Write the formula for the force exerted on the perfectly reflecting surface.
Here,
Conclusion:
Substitute
The force exerted on the perfectly reflecting surface is
(d)
The mass of the ice melted if the beam of laser is absorbed by an ice cube.
(d)
Answer to Problem 38P
The mass of the ice melted if the beam of laser is absorbed by an ice cube is
Explanation of Solution
The diameter of the beam of laser is
Write the formula for the mass of ice melted.
Here,
Conclusion:
Substitute
The mass of the ice melted if the beam of laser is absorbed by an ice cube is
Want to see more full solutions like this?
Chapter 40 Solutions
Physics: for Science.. With Modern. -Update (Looseleaf)
- A strip of metal foil with a mass of 5.00 × 10-7 kg is suspended in a vacuum and exposed to a pulse of light. The velocity of the foil changes from zero to 1.00 × 10-3 m/s in the same direction as the initial light pulse, and the light pulse is entirely reflected from the surface of the foil. Given that the wavelength of the light is 450 nm, and assuming that this wavelength is the same before and after the collision, how many photons in the pulse collide with the foil?arrow_forwardWhat is the minimum wavelength in m of the x-ray photons from a 140 kV x-ray tube? (h = 6.63x10-34J·s, 1 eV = 1.6x10-19 J, c = 3.0x108 m/sarrow_forwardA pulsed ruby laser emits light at 694.3 nm. For a 14.7-ps pulse containing 3.40 J of energy, find the following. (a) the physical length of the pulse as it travels through space _________________mm(b) the number of photons in it__________________ photons(c) If the beam has a circular cross section 0.600 cm in diameter, find the number of photons per cubic millimeter. _______________photons/mm3arrow_forward
- A visible (red) emission spectral line for cadmium (Cd) occurs at wavelength λ = 655.980 nm. What is the magnitude of the energy change associated with the emission of exactly three moles of photons of light with this wavelength?arrow_forwardH5. A Ti:Sapphire laser has a wavelength of 1200 nm and a pulse of duration 12 fs. If the total energy of the pulse is 2.4 J how many photons are emitted in one pulse? Group of answer choices 1.6 × 1017 3.2 × 1017 9.9 × 1019 1.45 x 1019 4.8 × 1019 A flat plane mirrors will make an image which Group of answer choices are always the same size as the actual object. could be smaller, larger, or the same size as the actual object, depending on the placement of the object. are always larger than the actual object. are always smaller than the actual object.arrow_forwardAn AM radio station broadcasts an electromagnetic wave with a frequency of 876 kHz, whereas an FM station broadcasts an electromagnetic wave with a frequency of 97.8 MHz. How many AM photons are needed to have a total energy equal to that of one FM photon?arrow_forward
- A light beam of wavelength 460 nm and intensity 180 W/m^2 shines on a target of area 1.69 m^2 for a duration of 4.25 s. How many photons from the light beam will have struck the target during this time?arrow_forwardA certain helium-neon laser pointer, emitting light with a wavelength of 632 nm, has a beam with an intensity of 715 W/m2 and a diameter of 2.70 mm. How many photons are emitted by the laser pointer every second? Thank you for the help!arrow_forwardThe power of a red laser (λ = 630 nm) is 3.00 watts (abbreviated W, where 1 W = 1 J/s). How many photons per second does the laser emit?arrow_forward
- The work function of tungsten is 4.5 eV. What is the photoelectric threshold wavelength for tungsten? What type of radiation is this? h = 4.136 x 10-15 eV.s c = 3.0 x 108 m/sarrow_forwardA certain heat lamp emits 230 W of mostly IR radiation averaging 1,420 nm in wavelength. (a) What is the average photon energy in joules? J (b) How many of these photons are required to increase the temperature of a person's shoulder by 2.0°C, assuming the affected mass is 4.0 kg with a specific heat of 0.83 kcal/(kg · °C). Also assume no other significant heat transfer. (c) How long does this take (in s), assuming all radiation emitted by the heat lamp is absorbed by the person's shoulder? s †arrow_forwardA photon with an energy of 2.24 eV strikes a photoemissive surface whose work function is 1.57 eV. Calculate the threshold frequency for the surface. 1.68 E 14 Hz 3.79 E 14 Hz 5.04 E 14 Hz 7.25 E 14 Hzarrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillModern PhysicsPhysicsISBN:9781111794378Author:Raymond A. Serway, Clement J. Moses, Curt A. MoyerPublisher:Cengage Learning