Answer:
The energy is 
(a) is correct option
Explanation:
Given that,
Energy = 4480 j
Weight of nitrogen = 20 g
Boil temperature = 77 K
Pressure = 1 atm
We need to calculate the internal energy
Using first law of thermodynamics


Put the value into the formula



We need to calculate the number of molecules in 20 g N₂
Using formula of number of molecules

Put the value into the formula


We need to calculate the energy
Using formula of energy

Put the value into the formula


Hence, The energy is 
Keep a first aid kit around
extra battery’s
extra water and food
have spare money set aside
be prepared for power outage
protect ur house with woof if necessary
keep surrounding yard clean of any big material
Answer: B
Explanation:
The reactivity of alkaline metal ( example group one ) increases down the group because of the increase in atomic mass from the top to the bottom of the group. As the mass increases, the force between the nucleus and the valence electron gets weaker and the atom will easily give up the electron as a result of this which eventually increases its reactivity.
The reactivity of halogens decreases as atomic mass increases. Therefore, option B is the correct answer.
Answer:
a is 4.6 x 10-2m
b is 1x8204m
Explanation:
The fire net is actually going past zero into a negative vertical displacement. Essentially because again, we're saying that why initial equals thirty eight meters. The person is falling down to zero meters. Zero meters is where the fire that is. And then after the person stretches the fire. Yet it has a certain vertical displacement. But this particles placement is negative. So here we're going to choose the negative value. so trying to see how much of the fire net would stretch if the person was lying on tough it and if the person jumped from a height of thirty eight meters. So for here Mass is going to be equal to sixty two kilograms and why initial for party is going to be twenty meters and then why final is going to be negative one point four meters And so in order to find in order to find this is an instance, essentially, this is an instance perspective in the sense that we need this data in order to figure out this during constant so we can see that energy initial equals energy final and then we consider it mg y initial equals mg.