A 6.00 cm tall light bulb is placed a distance of 54.2 cm from a double convex lens having a focal length of 12.7 cm. Determine the image distance. Round to one decimal
point

1 / f = 1 / i + 1 / o       thin lens equation

1 / i = 1 / f - 1 / o    =    (o - f) / (o * f)

i = o * f / (o - f)

i = 54.2 * 12.7 / (54.2 - 12.7) = 16.6 cm    image distance

Image is real and inverted and 16.6 / 54.2 * 6 = 1.94 cm tall

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

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.