Lecture 3 The effect of the magnetic field on the moving charge-The general review of the physical and difficult points of the 2013 college entrance examination. As shown in the figure on the right, a beam of electrons enters the solenoid along the axis, ignoring gravity, and the electron movement in the tube should be () A. When the current is fed from the end a, the electrons do a uniformly accelerated linear motion B. When the current is fed from the end b, the electrons do a uniformly accelerated linear motion C. No matter which end is fed with current, the electrons do a uniform circular motion D. No matter where the current is fed from, the electrons move at a constant linear speed [Analysis] The direction of the magnetic field inside the energized solenoid is along the axis of the solenoid, and the electron flow enters the solenoid along the axis, and the speed is parallel to the direction of the magnetic field. It is not affected by the Lorentz force, but performs uniform linear motion, the option D is correct.
Bird netting or bird netting is a form of bird pest control. It is a net used to prevent birds from reaching certain areas.
Bird netting comes in many shapes and forms, the most common being small mesh (1 or 2cm square), made from extruded and bidirectional polypropylene or woven polyethylene.
The most commonly used colors are black, white or green bird netting
Professional bird netting comes in large rolls, saving the farmer or aquaculturer a lot of money. Retail chains and local stores will offer smaller packages to meet the needs of backyard gardeners.
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