The diffusion coefficients for silver in copper are given at two temperatures: VMSE: D0 and Qd from Experimental Data T (°C) D (m2/s) 650 5.5 × 10−16 900 1.3 × 10−13 (a) Determine the values of D0 and Qd. (b) What is the magnitude of D at 875°C?

Explanation:

From the formula;

When T = 923 K and D = 5.5 x 10-16 m2/s

923 x R = Qd / [lnDo - ln(5.5 x 10-16 m2/s)] (1)

When T = 1173 K and D = 1.3 x 10-13 m2/s

Plugging the values ; and dividing equation 1 by 2

1173 x R = Qd / [lnDo - ln(1.3 x 10-13 m2/s)] (2)

b) T = 875°C = 875+273 = 1148K

Hence 1148 x 8.314 JK-1mol-1 = 196783.83 J / [ln(7.54x10-5 m2/s) - lnD]

D = 8.38x10-14 m2/s

true

explanation:

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.