<u>Answer</u>
46,200 J
The energy of given out when a substance is losing heat is given by:
H = mcΔθ
Where m is the mass of the substance,
c is the specific heat capacity of the substance and
Δθ is the temperature change.
H = 0.50 × 22 4200
= 46,200 Joules.
Wood, water, Forests. The rest can have harm to the nature.
(a) 
The change in potential energy of the electron is given by:

where
is the magnitude of the electron's charge
is the magnitude of the electric field
d = 520 m is the distance through which the electron has moved
Substituting into the equation, we find

(b) 78 kV
The potential difference the electron has moved through is given by

where
is the magnitude of the electric field
d = 520 m is the distance through which the electron has moved
Substituting into the equation, we find

Salt water offers the least electrical resistance.
<u>Explanation:</u>
Least electrical resistance indicates that any material which readily allows the electric current through itself, and shows more conductivity.
Here pure water doesn't contain any ions, so it is a bad conductor.
Wood and glass are also bad conductors of electricity.
Salt water contains ions, which conducts electricity which means it shows least electrical resistance.
Answer:
2 × 10⁸J/kg
Explanation:
Specific latent heat of vaporization (steam) is the quantity of heat required or needed to change a unit of mass of liquid to gaseous state at constant temperature (boiling point) and pressure.
It can be calculated mathematically using,
Q = mL
Where, Q = quantity of heat
m= mass in kg
L = specific latent heat (J/kg)
Therefore,from the question
Q= 15000000J
mass (m) = 75g = 75/1000 kg = 0.075kg
Q = mL
L = Q/m
L = 15000000 ÷ 0.075
L= 200000000J/kg
L = 2 × 10⁸J/kg
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