Two beams of coherent light travel different paths, arriving at point p. if the maximum destructive interference is to occur at point p, what should be the path difference between the two waves?

the path difference between the two waves should be one and one-quarter of a wavelengths.
the path difference between the two waves should be two wavelengths.
the path difference between the two waves should be one-half of a wavelength.
the path difference between the two waves should be one wavelength.
the path difference between the two waves should be one-quarter of a wavelength.
the path difference between the two waves should be four wavelengths

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.

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87

The radius of an atom is closest in size to a