Ι variant
1. Which of the following waves are transverse waves: 1 – waves on the surface of water, 2 – sound waves in gases, 3 – radio waves, 4 – ultrasonic waves in liquids?
A) Only 1. B) 1 and 3. C) 2 and 4. D) 1, 2, 3, and 4.
2. What determines the pitch of a sound?
A) The frequency of the vibrations. B.) The length of the wave. C) The amplitude of an oscillation. D) The phase of the vibrations.
3. In which media can longitudinal waves propagate?
A) Only in solid media. B) Only in liquid media. C) Only in gaseous media.
D) In gaseous, liquid, and solid media.
4. Consider the cases of electron motion:
1) the electron moves uniformly; 2) the electron makes vibrational motions;
3)the electron moves with acceleration.
In which cases does the emission of electromagnetic waves occur?
A) Only in the 1st. B) Only in the 2nd. C) Only in the 3rd.
5. A radio transmitter radiates electromagnetic waves with frequency ν. How should the capacitance
of the oscillating circuit of a radio transmitter so that it radiates electromagnetic waves with a frequency ν/2?
A) Increase it by a factor of 2. B) Reduce it by a factor of 2. C) Increase by a factor of 4.
6. From the statements, choose the correct one:
1)a variable electric field produces a variable magnetic field;
2)A variable magnetic field produces a variable electric field.
A)Only 1. B)Only 2. C)Both 1 and 2. D)Both statements are incorrect.
7. Name a device that produces high frequency electromagnetic oscillations:
A)High frequency generator. B)Modulating device. C)Transmitting antenna.
8. Electromagnetic waves differ from sound waves:
A)The presence of diffraction. Б). Propagation in matter. C) propagating in a vacuum.
9. An open oscillating circuit was first used to produce electromagnetic waves:
A) A. Popov. B) G. Marconi. C) M. Faraday. D) Hertz.
Solve the problem
1. The oscillation frequency of a wave source is 0.2 Hz, the speed of propagation of the wave is 10 m/s. What is the length of the wave?
2. The length of the wave is 0.1 m, the speed of its propagation is 0.5 m/s. What is the period of oscillation equal?
3. What is the length of an electromagnetic wave if a radio station transmits at a frequency of 75 MHz?
4. In what wavelength range can a radio receiver operate in which the inductance can vary from 0.1 to 10 μH and the capacitance can vary from 50 to 5000pF?
“Mechanical and electromagnetic waves”
The Ι variant
1. Which of the following waves are longitudinal waves: 1 – waves on the surface of water, 2 – sound
waves in gases, 3 – radio waves, 4 – ultrasonic waves in liquids?
A) Only 1. B) 1 and 3. C) 2 and 4. D) 1, 2, 3, and 4.
2. What determines the volume of a sound?
A) The amplitude of the vibrations. B) The phase of the vibrations. C) The length of the wave.
D) The speed at which the sound wave propagates.
3. In which media can transverse waves propagate?
A) Only in solid media. B) Only in liquid media. C) Only in gaseous media.
D) In gaseous, liquid and solid media.
4. Consider two cases of electron motion:
1) the electron moves uniformly and in a straight line;
2) the electron moves with equal acceleration and in a straight line.
In which cases does the emission of electromagnetic waves occur?
A) Only in 1. B) Only in the 2nd case. C) In both cases.
5. A radio transmitter radiates electromagnetic waves with frequency ν. How should the capacitance
of the oscillating circuit of a radio transmitter so that it radiates electromagnetic waves with a frequency of 2ν?
A) Increase it by a factor of 2. B) Reduce it by a factor of 4. C) Increase by a factor of 4.
6. When electromagnetic waves pass through air, oscillations occur:
A) air molecules; B) air density; C) electric field strength and magnetic field induction.
7. Name the device in which electromagnetic oscillations are converted into sound vibrations:
A)High frequency generator. B) a modulating device. C) a loudspeaker.
8. The basic property of all waves regardless of their nature is:
A)the presence of velocity; B)the presence of an oscillatory process; C)the transfer of energy without the transfer of matter.
9. The first radio receiver in the world, having applied in its circuitry a sensing element-coupler, constructed:
A) A.Popov. B) G. Marconi. C) Faraday. D) Hertz.
Solve the problems.
1. The wavelength is 40 m, its speed of propagation is 20 m/s. What is the frequency of oscillation of the wave source
waves?
2. The length of the wave is 1 km, the period of oscillation is 25 s. What is the speed of propagation of the wave?
3. In a radio receiver, one of the shortwave bands can receive transmissions
24m to 26m. What is the frequency range?
4.The oscillating circuit of a radio receiver is tuned to a wavelength of 300m.It has a 50mGn inductance coil. What is the electrical capacitance of the capacitor in the circuit?