So small () that the most powerful microscopes cannot detect them. A: are these particles B: were these particles C: these particles are D: these particles were

下列穿透能力最强的粒子是（ ）？ A: β-particles B: α-particles C: Microwave D: X-ray

The amount of scattering that occurs depends on the ( ). A: Size of particles B: Radiation wavelength C: Quantity of particles D: How deep the energy passes through the atmosphere

Which of the following is the bulk volume of the powder？ A: True volume B: Void volume between particles C: Void volume in particles D: The sum of the above three

What isthe essential characteristic of colloid? A: Tyndall effect B: Brownian motion C: Colloidal particles size ranges from1nmto 100nm D: colloidal particles charged

The particles are put into a vacuum with a/an ______ amount of heat, which turns the ice into steam, leaving the ground particles dry and ready for use. A: abstract B: minimal C: symbolic D: potential

下列穿透能力最强的粒子是（）？ A: X-ray B: [img=12x14]1802e152cb760b7.png[/img] particles C: [img=11x23]1802e152d3b7911.png[/img] particles D: Microwave

The function of coalescer in the 2nd chamber is to ______. A: Allow small particles of oil to coagulate B: Allow larger particles of oil to escape C: Prevent clogged strainer D: Prevent the damage of fine filter

微粒(particles) 越小,它们运动得越自由(freely)。

4. According to the deputy director, what is used to pick up particles?