1)a mirror can take far-away light and focus it so that the object being viewed, such as the moon or a star, can be seen as if it were much closer. a. flat b. convex c. concave d. diffracting2)a magnifying lens permits sunlight to travel through it and come to a focus on the other side. what type of lens would have this effect? a. flat  b. convex  c. concave  d. diffracting3)due to the doppler effect, if  an ambulance had its siren on and was moving towards you, the pitch you would hear would be the pitch the ambulance driver would hear. a.lower than  b. higher than  c. the same as  d. it would depend on the amplitude of the siren's sound waves.

Na food processing facility, a spherical container of inner radius r1 5 40 cm, outer radius r2 5 41 cm, and ther- mal conductivity k 5 1.5 w/m · k is used to store hot water and to keep it at 100°c at all times. to accomplish this, the outer surface of the container is wrapped with a 800-w electric strip heater and then insulated. the temperature of the inner surface of the container is observed to be nearly 120°c at all times. as- suming 10 percent of the heat generated in the heater is lost through the insulation, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the container, (b) obtain a relation for the variation of temperature in the container material by solving the differential equation, and (c) evaluate the outer surface tempera- ture of the container. also determine how much water at 100°c this tank can supply steadily if the cold water enters at 20°c.

Awave with a frequency of 500 hz is traveling at a speed of 100 m/s. what is the wavelength?

Does the distance travelled by an oscillating mass between times t=0 and t2 equal the displacement of the particle over the same time period if t2> t/2? hint: consider a sine wave starting at t1=0, then consider a closing wave starting at t1=0, for your explanation.