The most exact answer is 78.4J also in this kind of options we can say answer "d"
Answer:
Option B, Fix the piston in place so the volume of the pas remains constant
Explanation:
As we know

The effect on variable due to another variable can be studied by keeping the third variable constant.
Hence, in order the study the variation of temperature with pressure or vice versa, the volume needs to fixed at a certain value.
Hence, option B is correct
Answer:

Explanation:
Give that,
The potential difference of the electrons, 
We need to find the wavelength of the electrons.
Using the conservation of energy,

Put all the values,

So, the wavelength of the electrons is
.
Answer: C and D
Explanation: I’m pretty sure it’s C and D I got the same question but cold water let me know please, thanks!
Answer:
M=28.88 gm/mol
Explanation:
Given that
T= 95 K
P= 1.6 atm
V= 4.87 L
m = 28.6 g
R=0.08206L atm .mol .K
We know that gas equation for ideal gas
P V = n R T
P=Pressure , V=Volume ,n=Moles,T= Temperature ,R=gas constant
Now by putting the values
P V = n R T
1.6 x 4.87 = n x 0.08206 x 95
n=0.99 moles
We know that number of moles given as

M=Molar mass


M=28.88 gm/mol