The radium isotope 223Ra, an alpha emitter, has a half-life of 11.43 days. You happen to have a 1.0 g cube of 223Ra, so you decide to use it to boil water for tea. You fill a well-insulated container with 460 mL of water at 16∘ and drop in the cube of radium. How long will it take the water to boil?
Express your answer with the appropriate units.

Atomic nuclei of almost all elements consist of

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?