Answer:
1.98 atm
Explanation:
Given that:
Temperature = 28.0 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15  
So,  
T₁ = (28 + 273.15) K = 301.15 K 
n = 1 
V = 0.500 L
Using ideal gas equation as:
PV=nRT
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 = 0.0821 L atm/ K mol  
Applying the equation as:
P × 0.500 L = 1 ×0.0821 L atm/ K mol  × 301.15 K 
⇒P (ideal) = 49.45 atm
Using Van der Waal's equation
 
R = 0.0821 L atm/ K mol  
Where, a and b are constants.
For Ar, given that:
So, a = 1.345 atm L² / mol²
b =  0.03219 L / mol
So,  
 


⇒P  (real) = 47.47 atm
Difference in pressure = 49.45 atm - 47.47 atm = 1.98 atm
 
        
             
        
        
        
<span>11.823 cm
There is a slight ambiguity with this question in that I don't know if the measurements are from the surface of the ball, or the center of the ball. I will take this question literally and as such the point light source will be 124 cm from the wall.
The key thing to remember is that ball won't be showing an effective diameter of 4 cm to the light source. Instead the shadow line is a tangent to the ball's surface. There is a right triangle where the hypotenuse is the distance from the center of the ball to the light source (42 cm), one leg of the triangle is the radius (2cm). That right triangle will define a chord that will be the effective diameter of the disk casting the shadow. The cosine of the half angle of the chord will be 2/42 = 1/21. The sine of the half angle then becomes sqrt(1-(1/21)^2) = sqrt(440/441) = 2sqrt(110) = 0.99886557. Now multiply that sine by 4 (radius of ball multiplied by 2 since it's the half angle and we want the full side of the chord) and we get an effective diameter of 3.995462279 cm.
Now we need to calculate the effective distance that circle is from the wall. It will be slightly larger than 82 cm. The exact value will be 82 + cos(half angle) * radius. So
82 + 1/21 * 2 = 82 + 2/21 = 82.0952381
Now we have the following dimensions with a circle replacing the ball in the original problem.
Distance from wall to effective circle = 82.0952381 cm
Distance from effective circle to point source = 124 - 82.0952381 = 41.9047619 cm
Effective diameter of circle = 3.995462279 cm
And because the geometry makes similar triangles, the following ratio applies.
3.995462279/41.9047619 = X/124
Now solve for X
3.995462279/41.9047619 = X/124
124*3.995462279/41.9047619 = X
495.4373226/41.9047619 = X
11.82293611 = X
The shadow cast on the wall will be a circle with a diameter of 11.823 cm</span>
        
             
        
        
        
Hello!
Yes, someone with an IQ score of 120 can be gifted. 
An IQ score of 120 means that the individual is moderately gifted. Although this IQ doesn't qualify for gifted education programs, research shows that people with IQs of about 145-180 don't perform significantly better than people with 120s IQ in terms of success. 
As an example, professor Dean Simonton from the University of California found that an optimum leader should have an IQ in the 120-125 range, so having an IQ of 120 would mean that the individual is gifted for leadership.
Have a nice day!
        
                    
             
        
        
        
They are the physics of the world??