The minimum energy required to cause an electron to be emitted from a clean zinc surface is 6.9 x 10^-19. (a) Calculate the maximum wavelength of electromagnetic radiation which will cause an electron to be emitted from the clean zinc surface.

(b)What would be the effect of irradiating a clean zinc surface with radition of wavelength 4.0x 10^-7? You must justify your answer.

All cells are made of four types of acids, lipids, proteins, and carbohydrates.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

Draw the structure for 5-isopropyl-2-methyl-3-nonene