The distance from earth to the center of our galaxy is about 27,000 ly (1 ly = 1 light year = 9.47 × 10^15 m), as measured by an earth-based observer. a spaceship is to make this journey at a speed of 0.9990c. according to a clock on board the spaceship, how long will it take to make the trip? express your answer in years. (1 yr is equal to 3.16 × 10^7 s.)

The time is 1206 years.

Explanation:

Given that,

Distance = 27000 ly

Speed = 0.9990c

We need to calculate the time

Using formula of speed

Put the value into the formula

We need to calculate the time dilation the clock on the spaceship

Using formula of dilation time

The time convert in years

We know that,

So, the time is

Hence, The time is 1206 years.

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.