Task 3.1
A material point with a mass of 7.1 g performs a harmonic oscillation with an amplitude of 2 cm and a frequency of 5 Hz.
What is the maximum restoring force and total energy of oscillations?
PROBLEM 3.11
In a vacuum, a plane electromagnetic wave propagates. The amplitude of the magnetic
Wave field of 0.1 A / m. Determine the amplitude of the electric field strength of the wave and the mean
Time energy density of the wave.

PROBLEM 3.21
The distance between the two coherent sources is 0.9 mm, and the distance from the sources to the screen is 1.5 m.
The sources emit monochromatic light with a wavelength of 0.6 μm. Determine the number
Interference fringes per 1 cm of the screen.

Task 3.31
A parallel beam of light from a monochromatic source (? = 0.5 μm) falls normally on
Diaphragm with a round hole diameter of 1 mm. Dark or light will be the center of diffraction
Picture on the screen, located at a distance of 0.5 m from the diaphragm?

Task 3.41
At what angle should the sun be to the horizon, so that its rays reflected from the surface
Water, were maximally polarized?

Task 3.51
Calculate the group and phase velocities of light with a wavelength of 643.8 nm in water, if it is known that
The refractive index for this wavelength is 1.3314, and for a wavelength of 656.3 nm it is equal to
1,3311.

Task 3.61
Determine the wavelength corresponding to the maximum emissivity of a blackbody at
Temperature 37 ° С and energy luminosity of the body.
Task 3.71
Determine the maximum speed of photoelectrons emitted from a tungsten electrode,
Illuminated by ultraviolet light with a wavelength of 0.2 μm.