A kingfisher bird that is perched on a branch a few feet above the water is viewed by a scuba diver submerged beneath the surfac
1 answer:
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Answer:
ΔH = -45.1872 kJ , where negative sign signifies heat loss.
Q = ΔH = -45.1872 kJ , where negative sign signifies heat loss.
S system = -0.141 kJ/K
S surroundings = 0.1536 kJ/K
S universe = -0.141 kJ/K + 0.1536 kJ/K = 0.0126 kJ/K
Explanation:
Given:
Cp = 4. 184 J/(mole. K)
T₁ = 75 ⁰C
T₂ = 21 ⁰C
Mass of water = 200 g = 0.2 kg
Since,
ΔH = 0.2*4.184*(21-75) kJ
<u> ΔH = -45.1872 kJ , where negative sign signifies heat loss.</u>
Since the process is at constant pressure
<u> Q = ΔH = -45.1872 kJ , where negative sign signifies heat loss.</u>
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
T₁ = 75 ⁰C = 348 .15 K
T₂ = 21 ⁰C = 294.15 K
The entropy of the water is given by:
<u> S = m×Cp×ln(T₂ /T₁) </u>
S = 0.2*4.184*ln(294.15/348.15)
<u> S system = -0.141 kJ/K</u>
The heat gain by surroundings
<u> dQ = -Qreaction = 45.1872 kJ </u>
The entropy change of surroundings is
S surr = dQ/T₂ = 45.1872/294 .15
<u> S surr = 0.1536 kJ/K </u>
The entropy of universe is the sum total of the entropy of the system and the surroundings and thus,
S universe = Ssys + Ssurr
<u> S universe = -0.141 kJ/K + 0.1536 kJ/K = 0.0126 kJ/K</u>
Answer:
The correct option is 'c': The Force vector (F) and the magnetic field vector (B) are always perpendicular.
Explanation:
The magnetic force that acts on a charged particle moving in a magnetic field is given by
As we can see that vector cross product is involved hence we conclude that Force vector (F) is always perpendicular to both the velocity vector (v) and the magnetic field vector (B) which may be at any angle with respect to each other.
Hence we conclude that vectors F and B are always perpendicular.
(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