Power is a measure of the rate of energy or work done on a system. It has units of energy per time. In SI, Joules per second and is equal to the units of Watts. So, for an 800 Watts hair straightener, the energy transfer per second would be 800 Joules.
Explanation:
The given data is as follows.
= 0.8 kg/s = 800 g, 
= 1 kg = 1000 g,
= (75 - T),
= T - 25
Now, according to the law of conservation of energy,

+ 30000
250.8 - 3.34T = 4.18T - 104.5 + 30
T = 
= 
Thus, we can conclude that temperature of the warm water stream is
.
When the current flow ceases, the magnetic flow also decreases
Answer:
1.11
Explanation:
The index of the medium can be calculated using below formula
V= c/ n ............eqn(1)
Where V= velocity of the light is reduced to while traveling through the second medium= 2.7 x 10^8 m/s
n= index of the medium
c= speed of light= 3 x 10^8 m/s
Substitute for the values in eqn(1)
2.7 x 10^8 = (3 x 10^8 m/s)/ n
Making " n" subject of the formula, we have
n= (3 x 10^8 )/(2.7 x 10^8)
n= 1.11
Hence, the index of the medium is 1.11