The graph below shows the decay of a radioactive isotope. what is the half-life of the isotope?
a. 15 seconds
b. 25 seconds
c. 40 seconds
d. 200 seconds
the graph is in an attachment. : )

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.

Will mark brainliest! asap! ! 16) which of the clouds shown would indicate a possible future rain storm? a) b) c) d)