Answer:
240 seconds
Explanation:
Data Given:
Distance Radio travel to earth = 7.19 ×10⁷ km
Speed of this radio signal = 3.00 ×10⁸ m/s
Solution:
First convert Km to m
1 km = 1000 m
7.19 ×10⁷ km = 7.19 ×10⁷ x 1000 = 7.19 × 10¹⁰m
Formula used to calculate time
Speed (S) = distance (d) / time (t)
rearrange above equation for time
time (t) = distance (d) / Speed (S) . . . . . . . . .(1)
Put values in equation 1
time (t) = 7.19 × 10¹⁰/ 3.00 ×10⁸ m/s
time (t) = 240 s
So 240 seconds it take for the signal to reach the earth
If you look at the periodic table of elements, you can see that atomic number for phosphorus is 15. It means that it has 15 electrons and 15 protons total. Now you can write configuration for P which is: 1s22s22p63s23p3. or [Ne] 3s2<span> 3p</span><span>3 </span><span>
From here, you can see that it has 5 valence electrons (s2+p3).
In the periodic table of elements the number of protons+ number of neutrons is determined as atomic mass. Atomic mass of the P is 30.
number of neutrons = atomic mass-atomic number
number of neutrons = 30-15
number of neutrons= 15 </span>
Answer:
the number of laps in the case when he run for 50 minutes is 18,333.33
Explanation:
The computation of the number of laps in the case when he run for 50 minutes is shown below:
Given that
He runs 440m lap in 1.2 minutes
So in 50 minutes he can have laps of
= 440 × 50 ÷ 1.2
= 18,333.33 laps
hence, the number of laps in the case when he run for 50 minutes is 18,333.33
Answer is (4).<span>
<em>
</em></span>
<span><em>Explanation:</em>
</span><span>
<span>The given mixture contains an </span>insoluble solid<span> <span>and an </span></span>aqueous solution of salt. <span>The insoluble solid is </span>sand. <span>
First </span><span>we have to separate </span>insoluble solid. <span>Sand can be separated by doing </span>filtration. When we filter the mixture sand can be seen as the residue on the filter paper.
<span>After filtering the mixture, we should collect the </span>filtrate. <span>Filtrate is the </span>salt solution. <span>By doing </span>evaporation <span>we can get the </span>solid salt. <span>
First </span>and second choices are wrong <span>because </span>after evaporating water filtration
cannot be done and salt and sand will be mixed together.<span>
Salt cannot be
filtered out because the salt is soluble and it is <span>in
aqueous medium. Hence, third choice is wrong</span></span></span>
Answer:
51 J
Explanation:
The air inside a bicycle tire pump has 27 joules of heat conducted away. By convention, when heat is released, it takes the negative sign, so Q = -27 J.
77.9 joules of work done are being done on the air inside a bicycle tire pump. By convention, when work is being done on the system, it takes the positive sign, so W = 77.9 J
We can calculate the change in the internal energy (ΔU) using the following expression.
ΔU = Q + W
ΔU = (-27 J) + 77.9 J
ΔU = 51 J
