Which statement best describes a physical change?
Changes can occur to certain chemical properties of the substance, but the overall shape of the substance will remain the
same.
Changes can occur to certain physical properties of the substance, but the overall shape of the substance will remain the
same.
Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.
Changes can occur to chemical properties of a substance, but the chemical composition of the substance remains the same.

it is called acid bonding

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

the formula for the conversion of temperature from degree celsius to kelvin is:

the sample of water at is converted to kelvin temperature by using the above formula as:

on comparing the two samples of water at or we can say that at and at respectively. the difference between the temperatures of two samples of water is:

hence, one can say that the sample of water at is greater than the sample of water at by .

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.