Answer: C. Expanding
Explanation:
When an object moves away from an observer, the light waves emitted by the object are stretched out making them have move towards the red end of the electromagnetic spectrum, where light has a longer wavelength. This phenomenon is known as the redshift (cosmological redshift). For most astronomical objects, the observed spectral lines are all shifted to longer wavelengths. It is caused solely by the expansion of the Universe and thus, the value of a redshift indicates the recession velocity of the expanding object, or its distance.
Redshift is opposed to the blueshift. Blue light wavelengths tend to be closer together hence blueshift light tends to be emitted from objects that are collapsing.
The formula for half-life is:

Where A is the amount of iodine-131 initially and after 40 days, t is time, h is half-life of the isotope. Let's plug in our values to the equation:

Therefore, the patient has 0.625 grams of iodine-131 after 40 days.
Answer: 
Explanation:
Given
Distance between two speakers is 8 m
Man is standing 12 away from the wall
When the person moves 3 parallel to the wall
the parallel distances from the speaker become 4+3, 4-3
Now, the difference of distances from the speaker is

Condition for destructive interference is

for second destructive interference; n=2

Answer:
Explanation:
Given
Motorcyclist speed=12 m/s
maximum acceleration
distance=39 m
Let x be the distance traveled by motorist in his reaction time
therefore remaining 39-x will be traveled with
acceleration

s=39-x
v=0
u=12 m/s

x=27 m
Therefore he traveled 27 m in his reaction time

t=2.25 s
(b)If his reaction time is 2.56 sec
then distance traveled in his reaction time

Remaining distance 39-30.72=8.28 m
therefore its velocity when it reaches the deer


v=6.681 m/s
Answer:
63.5 °C
Explanation:
The expression for the calculation of work done is shown below as:
Where, P is the pressure
is the change in volume
Also,
Considering the ideal gas equation as:-

where,
P is the pressure
V is the volume
n is the number of moles
T is the temperature
R is Gas constant having value = 8.314 J/ K mol
So,

Also, for change in volume at constant pressure, the above equation can be written as;-

So, putting in the expression of the work done, we get that:-
Given, initial temperature = 28.0 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (28.0 + 273.15) K = 301.15 K
W=1770 J
n = 6 moles
So,
Thus,


The temperature in Celsius = 336.63-273.15 °C = 63.5 °C
<u>The final temperature is:- 63.5 °C</u>