What must happen in the eye so we can focus on a very close object?

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?

Carbon 14 is a naturally occurring stable

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.