C. They don't have free electrons.
The only things capable of conducting a charge are things that have charged particles in them that are free to move, e.g free electrons, free positions, or dissociated ions
Answer: Thermal energy is 8,2 kJ
Explanation: Heat Q = m c ΔT . c = 385 J/kg C and
ΔT = (1085 - 25)C = 1060 C. Q = 0.020 kg · 385 J / (kg C) ·1060 C
= 8162 J
Answer:
a) 
b) 
Explanation:
Get the reactive powers for each of the loads:
Reactive power = Real Power * tanθ
For load 1
Active power, P₁ = 100 W
Power factor, 


For load 2
Active power, P₂ = 250 W
Power factor, 


For load 3
Active power, P₃ = 250 W
Power factor, 


Calculate the total reactive power, 

Calculate the total active power, 



V = 115 

b) Power factor of the composite load is 

Answer:
12.64968 Hz
Explanation:
v = Velocity of sound in seawater = 1522 m/s
u = Velocity of dolphin = 7.2 m/s
f' = Actual frequency = 2674 Hz
From Doppler effect we get the relation

The frequency that will be received is 2661.35032 Hz
The difference in the frequency will be
