Answer:
a) C = 4,012 10⁻¹⁴ F, b) Q = 1.6 10⁻¹¹ C
, c) U = 3.21 10⁻¹¹ J
Explanation:
a) The capacitance of a capacitor is
C = k e₀ A / d
Let's calculate
C = 4 8.85 10⁻¹² 17 10⁻⁴ / 0.150 10⁻²
C = 4,012 10⁻¹⁴ F
b) let's look the charge
C = Q / ΔV
Q = C ΔV
Q = 4,012 10⁻¹⁴ 400
Q = 1.6 10⁻¹¹ C
c) The stored energy
U = ½ C ΔV²
U = ½ 4,012 10⁻¹⁴ 400²
U = 3.21 10⁻¹¹ J
Answer:
1.2cm
Explanation:
V=(2ev/m)^1/2
=(2*1.6*10^19 x2500/ 1.67*10^27)^1/2
=6.2x10^5m/s
Radius of resulting path= MV/qB
= 1.67*10^-27x6.92*10^6/1.6*10^-16 x0.6
=0.012m
=1.2cm
Energy of a wave:
E = nhc/λ
3000 = (n x 6.63 x 10⁻³⁴ x 3 x 10⁸)/(510 x 10⁻⁹)
n = 7.69 x 10 ²¹ photons per second per meter²
2.70 cm² = 2.70/10,000 m²
= 2.7 x 10⁻⁴
Photons per second = 7.69 x 10 ²¹ x 2.7 x 10⁻⁴
= 2.08 x 10¹⁸ photons per second
Answer:
T = 76.39°C
Explanation:
given,
coffee cup temperature = 95°C
Room temperature= 20°C
expression
temperature at t = 0
T(0) = 95°C
temperature after half hour of cooling
t = 30 minutes
T(30) = 61.16° C
average of first half hour will be equal to
![T = \dfrac{1}{30}[(20t - \dfrac{75 e^{\dfrac{-t}{50}}}{\dfrac{1}{50}})]_0^30](https://tex.z-dn.net/?f=T%20%3D%20%5Cdfrac%7B1%7D%7B30%7D%5B%2820t%20-%20%5Cdfrac%7B75%20e%5E%7B%5Cdfrac%7B-t%7D%7B50%7D%7D%7D%7B%5Cdfrac%7B1%7D%7B50%7D%7D%29%5D_0%5E30)
![T = \dfrac{1}{30}[(20t - 3750e^{\dfrac{-t}{50}}]_0^30](https://tex.z-dn.net/?f=T%20%3D%20%5Cdfrac%7B1%7D%7B30%7D%5B%2820t%20-%203750e%5E%7B%5Cdfrac%7B-t%7D%7B50%7D%7D%5D_0%5E30)
![T = \dfrac{1}{30}[(20\times 30 - 3750 e^{\dfrac{-30}{50}} + 3750]](https://tex.z-dn.net/?f=T%20%3D%20%5Cdfrac%7B1%7D%7B30%7D%5B%2820%5Ctimes%2030%20-%203750%20e%5E%7B%5Cdfrac%7B-30%7D%7B50%7D%7D%20%2B%203750%5D)
![T = \dfrac{1}{30}[600 - 2058.04 + 3750]](https://tex.z-dn.net/?f=T%20%3D%20%5Cdfrac%7B1%7D%7B30%7D%5B600%20-%202058.04%20%2B%203750%5D)
T = 76.39°C
