Physics Wave Optics Level: High School
Dual Nature of Light
An owl has good night vision because its eyes can detect a light intensity as small as 5.0 10-13 W/m2 . What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 7.0 mm and the light has a wavelength of 545 nm ?
Physics Modern Physics Level: High School
Photoelectric Effect
A magnesium surface has a work function of 3.78 eV . Electromagnetic waves with a wavelength of 215 nm strikes the surface and eject electrons . Find the maximum kinetic energy of the ejected electrons . Express your answer in electron volts .
Physics Modern Physics Level: High School
Photoelectric Effect
Ultraviolet light with a frequency of 2.50 1015 Hz strikes a metal surface and ejects electrons that have a maximum kinetic energy of 6.9 eV . What is the work function (in eV) of the metal ?
Physics Relativity Level: High School
A spaceship is approaching the earth at a relative speed of 0.95 c . The mass of the ship is 3.0 107 kg . Find the magnitude of each of the following .a) the classical momentum of the ship .
b) the relative momentum of the ship .
Physics Relativity Level: High School
Mass Energy Equivalent
Three kilograms of water are heated from 20.0 degree to 59.0 degree C .a) How much heat is required to produce this change in temperature ? [The specific heat capacity of water is 4186 J/(kg degree C)]
b) By how much does the mass of the water increase ?
Physics Relativity Level: High School
Mass Energy Equivalent
Suppose one gallon of gasoline produces 1.1 108 J of energy , and this energy is sufficient to operate a particular car for 38 miles .An aspirin tablet has a mass of 320 mg . If the aspirin could be converted completely into thermal energy , how many miles would this car go on a single tablet ? Answer in units of miles .
Physics Relativity Level: High School
Mass Energy Equivalent
An electron and a positron each have a mass of 9.11 10-31 kg . They collide and both vanish , with only electromagnetic radiation appearing after the collision . If each particle is moving at a speed of 0.35 c relative to the laboratory before the collision . determine the energy of the electromagnetic radiation .
Physics Ray Optics Level: High School
Concave Mirror
A concave shaving mirror has a radius of curvature of +32.3 cm . It is positioned so that the (upright) image of a man’s face is 3.05 times the size of the face . How far is the mirror from the face
Physics Ray Optics Level: High School
Plane Mirror
A moth at about eye level is 7.8 cm in front of a plane mirror , you are behind the moth , 31 cm from the mirror . What is the distance between your eyes and the apparent position of the moth’s image in the mirror ?
Physics Ray Optics Level: High School
Total Internal Reflection
The index of refraction of a certain liquid is 2.7 . What is the critical angle for a light ray traveling in this liquid toward a flat layer of air above it ?
Physics Ray Optics Level: High School
Refraction
In the figure at “click here” , a 2.52 m-long vertical pole extends from the bottom of a swimming pool to a point 51.9 cm above the water . Sunlight is incident at angle 55.0 degree . What is the length in meters of the shadow of the pole on the level bottom of the pool ? The water has an index of refraction of 1.33 .
Physics Ray Optics Level: High School
Refraction
Light in vacuum is incident on the surface of a slab of transparent material . In the vacuum the beam makes an angle of 36.9 degree with the normal to the surface , while in the slab it makes an angle of 29.0 degree with the normal . What is the index of refraction of the transparent material ?Li = 36.9 degree
Lr = 29 degree
Index of refraction = micro = sin i / sin r
micro = sin 36.9 degree / sin 29 degree
= 1.238
Physics Modern Physics Level: High School
Bohr’s Atomic Model
Using the concept of standing waves , de Brogile was able to derive Bohr’s stationary orbit postulate . He assumed that a confined electron could exist only in states where its de Broglie waves form standing-wave patterns . Consider a particle confined in a box of length L and fixed at both ends . Apply de Broglie’s concept to shows that the linear momentum of this particle is quantized with p = mv = nh/2L and the allowed states correspond to particle energies of En = n^2Eo, where Eo = h^2/(8mL^2)
Physics Relativity Level: High School
A .110 nm photon collides with a stationary electron . After the collision the electronic moves forward and the photon recoils backwards . Find the momentum and kinetic energy of the electron . (The KE should be expressed in eV) .
Physics Properties Of Matter Level: High School
Fluids
Use Bernoulli’s equation to estimate the upward force on an airplane’s wing if the average flow speed of air is 192 m/s above the wing and 160 m/s below the wing . The density of the air is 1.1 kg/m^3 and the area of each wing surface is 26 m^2 .