I think is A or B it depends on like what the trying to answer
        
                    
             
        
        
        
Answer:
It's really important waves type for fulfill human's needs
Explanation:
Electromagnetic waves are transverse waves composed by the perpendicular oscillating electric and magnetic fields.
EM waves have both Electrical and magnetic features.
they travel in the velocity of light (3*10⁸ ms⁻¹)
they does not require any media to travel. It has two perpendicular electric field and the magnetic field which are perpendicular to each other
They travel perpendicular to each of those electric and magnetic fields.
Example :  
- Radio Wave
- Micro Wave
- IR wave
- Light Wave
- UV rays
- X rays
- Gamma rays
- Cosmic rays
The main importance of em waves is they allow energy to be stored within them and then can be propagated over a large distance using the dielectric and magnetic properties of materials .
This performance has been used in many fields wisely and effectively to make the things easy.
Ex : medicine , Telecommunication , energy , Engineering etc
 
        
             
        
        
        
Answer:
6 atm.
Explanation:
 Let the mass of both be m
Then moles of He = m/ 4
Moles of Ne = m/ 20
mole fraction of He = Moles of He/ Total moles = m/4/ (m/4 + m/20) = 0.25 m/0.3m = 0.83
Pressure of He = Mole fraction×total pressure = 0.83 × 6 atm = 5 atm 
 
        
             
        
        
        
Answer:
P(bat) = V²r/(R+r)²
Explanation:
Let the resistance of the coil be R
Internal resistance of the battery be r
Emf of the battery = V
Power dissipated in the internal resistance of the battery is normally given as P = I²r
where I is the current flowing in the circuit. 
From Ohm's law,
V = I R(eq)
R(eq) = (R + r)
I = V/(R+r)
P = I²r
P = [V/(R+r)]²r
P = V²r/(R+r)²
Hope this Helps!!!
 
        
             
        
        
        
Answer:
never lol
studying is your work
but why all are doing I don't know=_=