Answer:
A half-life is the time required for one half of the nuclei in a radio- active isotope to decay.
Explanation:
A radio-active isotope is an isotope which undergoes radioactive decay.
Radioactive decay is a spontaneous process in which the nucleus of an atom changes its state (turning into a different nucleus, or de-exciting), emitting radiation, which can be of three different types: alpha, beta or gamma.
The half-life of a radio-active isotope is the time required for half of the nuclei of the initial sample to decay.
The law of radio-active decay can be expressed as follows:

where
N(t) is the number of undecayed nuclei left at time t
N0 is the initial number of nuclei
t is the time
is the half-life
We see that when
(that means, when 1 half-life has passed), the number of undecayed nuclei left is

So, half of the initial nuclei.
Answer:

Explanation:
a. Internal energy and the relative specific volume at
are determined from A-17:
.
The relative specific volume at
is calculated from the compression ratio:

#from this, the temperature and enthalpy at state 2,
can be determined using interpolations
and
. The specific volume at
can then be determined as:

Specific volume,
:

The pressures at
is:

.The thermal efficiency=> maximum temperature at
can be obtained from the expansion work at constant pressure during 

b.Relative SV and enthalpy at
are obtained for the given temperature with interpolation with data from A-17 :
Relative SV at
is

=
Thermal efficiency occurs when the heat loss is equal to the internal energy decrease and heat gain equal to enthalpy increase;

Hence, the thermal efficiency is 0.563
c. The mean relative pressure is calculated from its standard definition:

Hence, the mean effective relative pressure is 674.95kPa
Properties of electromagnetic radiation and photons. ... we find the types of energy that are lower in frequency ( and thus longer in wavelength) than visible light. Seeee
Answer:
the time comes eventually.
Explanation:
ur body just be giving up