贝贝家要装修客厅，客厅是一个长8米，宽6米，高4米的长方体。需要粉刷客厅的四周和天花板，除去门窗面积10平方米，每平方米需要涂料1升。现在有两种包装的涂料：一种容量5升，每桶45元；一种容量8升，每桶68元。购买哪种涂料更省钱？
8×4×2+6×4×2+8×6-10=150（m2），1×150=150（升），150÷5×45=1350（元），150÷8≈19（桶），19×68=1292（元），购买容量8升的涂料。
| Awarded the Nobel Prize for physics in 1918, German physicist Max Planck is best remembered as the originator of the quantum theory. His work helped usher in a new era in theoretical physics and revolutionized the scientific community’s understanding of atomic and subatomic processes. Planck introduced an idea that led to the quantum theory, which became the foundation of twentieth century physics. In December 1900, Planck worked out an equation that described the distribution of radiation accurately over the range of low to high frequencies. He had developed a theory which depended on a model of matter that seemed very strange at the time. The model required the emission of electromagnetic radiation in small chunks or particles. These particles were later called quantums. The energy associated with each quantum is measured by multiplying the frequency of the radiation, v, by a universal constant, h. Thus, energy, or E, equals hv. The constant, h, is known as Planck’s constant. It is now recognized as one of the fundamental constants of the world. Planck announced his findings in 1900, but it was years before the full consequences of his revolutionary quantum theory were recognized. Throughout his life, Planck made significant contributions to optics, thermodynamics and statistical mechanics, physical chemistry, among other fields. |
It can be inferred from the passage that Planck’s work led to the development of which of the following
A．The rocket.
B．The atomic bomb.
C．The internal combustion engine.
D．The computer.