Answers:
a) 
b) 
c) 
d) 46000 s
Explanation:
<h2>a) Time for one cycle of the radio wave</h2>
We know the maser radiowave has a frequency
of 
In addition we know there is an inverse relation between frequency and time
:
(1)
Isolating
:
(2)
(3)
(4) This is the time for 1 cycle
<h2>
b) Cycles that occur in 1 h</h2>
If
and we already know the amount of cycles per second
, then:
This is the number of cycles in an hour
<h2>c) How many cycles would have occurred during the age of the earth, which is estimated to be

?</h2>
Firstly, we have to convert this from years to seconds:

Now we have to multiply this value for the frequency of the maser radiowave:
This is the number of cycles in the age of the Earth
<h2>
d) By how many seconds would a hydrogen maser clock be off after a time interval equal to the age of the earth?</h2>
If we have 1 second out for every 100,000 years, then:

This means the maser would be 46000 s off after a time interval equal to the age of the earth
The correct answer of this question is : A) Change alternating current into direct current.
EXPLANATION :
As per the question, we are given vacuum tube. Vacuum tube can be of various types. Normally it contains two electrodes called cathode and anode which are enclosed in an evacuated glass chamber . There are also other types of vacuum tubes which contain extra electrodes like control grid .
The vacuum tube can be used as a rectifier. It means that it can be used as an electronic device which will convert alternating current into direct current. It may be a half wave rectifier or a full wave rectifier. Actually the direct current obtained during the rectification of alternating current is pulsating in nature.
Hence, the correct answer is that a vacuum tube can be used to change alternating current into direct current.
Answer:
32.46m/s
Explanation:
Hello,
To solve this exercise we must be clear that the ball moves with constant acceleration with the value of gravity = 9.81m / S ^ 2
A body that moves with constant acceleration means that it moves in "a uniformly accelerated motion", which means that if the velocity is plotted with respect to time we will find a line and its slope will be the value of the acceleration, it determines how much it changes the speed with respect to time.
When performing a mathematical demonstration, it is found that the equations that define this movement are the follow

Where
Vf = final speed
Vo = Initial speed
=7.3m/S
A = g=acceleration
=9.81m/s^2
X = displacement
=51m}
solving for Vf

the speed with the ball hits the ground is 32.46m/s
Both particles and big objects will be influenced by each other less if they are moved further apart.