Вопрос
Physics paper 9. 1. Answer the question in detail:Radioactivity, it's nature. Types of radioactive decay: alpha - decay, beta -decay, y-radiation. 2. Solve the problems A) Find the amplitude the circular (cyclic)frequency, the frequency the period of oscillations and the initial phase of mechanical pendulum , if its deflection S: a function of time is described by the equation S=0.7cos(pi t)m .Draw the graph of this osciliations. B) The audio frequency range extends from 20 Hz to 20000 Hz. Calculate the wavelength range of sound. The speed of sound is 330ms^-1
Решения
4.1
(334 Голоса)
Никанор
элита · Репетитор 8 лет
Ответ
1. Radioactivity is the phenomenon in which unstable atomic nuclei lose energy by emitting radiation in the form of alpha particles, beta particles, or gamma rays. The nature of radioactivity is that it is a spontaneous process that occurs naturally in certain elements.There are three main types of radioactive decay:a) Alpha decay: In alpha decay, an alpha particle (which consists of two protons and two neutrons) is emitted from the nucleus of the radioactive atom. This results in the formation of a new atom with a lower atomic number and mass number.b) Beta decay: In beta decay, a neutron in the nucleus of the radioactive atom is converted into a proton, and an electron (called a beta particle) is emitted. This increases the atomic number of the resulting atom by one, while the mass number remains unchanged.c) Gamma radiation: Gamma radiation is the emission of high-energy electromagnetic radiation from the nucleus of a radioactive atom. It is the most penetrating form of radiation and can pass through several centimeters of human tissue.2. A) To find the amplitude, circular frequency, frequency, period of oscillations, and initial phase of the mechanical pendulum, we can use the given equation for the deflection S as a function of time:S = 0.7cos(πt)The amplitude of the oscillation is the maximum displacement from the equilibrium position, which is 0.7 m in this case.The circular frequency (ω) is the constant that determines the rate of oscillation, and it is given by the coefficient of t in the cosine function. In this case, ω = π rad/s.The frequency (f) is the number of oscillations per unit time, and it is related to the circular frequency by the equation ω = 2πf. Therefore, f = ω/2π = π/2π = 1/2 Hz.The period (T) is the time it takes for one complete oscillation, and it is the reciprocal of the frequency. Therefore, T = 1/f = 1/(1/2) = 2 s.The initial phase is the phase of the oscillation at t = 0, which is 0 in this case.B) To calculate the wavelength range of sound, we can use the formula:Wavelength (λ) = Speed of sound (v) / Frequency (f)Given that the speed of sound is 330 m/s and the audio frequency range extends from 20 Hz to 20,000 Hz, we can calculate the wavelength range as follows:For the lowest frequency (20 Hz):λ = 330 m/s / 20 Hz = 16.5 mFor the highest frequency (20,000 Hz):λ = 330 m/s / 20,000 Hz = 0.0165 mTherefore, the wavelength range of sound is from 0.0165 m to 16.5 m.