As the velocity of the sound source approaches the speed of sound, the wave fronts ahead of the object begin to appear as:

a-separately distinguishable waves

b-a single wave front
c-cylindrical
d-a cone shape shockwave.
Term 1

and when the velocity of the sound source exceeds the speed of sound, the wave fronts form:

Term 2

a-separately distinguishable waves

b-a single wave front
c-cylindrical
d-a cone shape shockwave.

The correct answer is D

shock waves

Explanation:

When a body approaches the speed of sound in the media, the waves it emits are getting closer and closer to each other, the envelope (sum) results in a kind of cylindrical cone that is similar to that formed in a supersonic process

The correct answer is D

When the speed of sound is exceeded, the body goes faster than the wave, so the so-called shock waves are formed.

  They carry a lot of energy

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.

i think it's 35 meters