The potential difference across the parallel plate capacitor is 2.26 millivolts
<h3>Capacitance of a parallel plate capacitor</h3>
The capacitance of the parallel plate capacitor is given by C = ε₀A/d where 
- ε₀ = permittivity of free space = 8.854 × 10⁻¹² F/m, 
- A = area of plates and 
- d = distance between plates = 4.0 mm = 4.0 × 10⁻³ m.
<h3>Charge on plates</h3>
Also, the surface charge on the capacitor Q = σA where 
- σ = charge density = 5.0 pC/m² = 5.0 × 10⁻¹² C/m² and 
- a = area of plates.
<h3>
The potential difference across the parallel plate capacitor</h3>
The potential difference across the parallel plate capacitor is V = Q/C 
= σA ÷ ε₀A/d 
= σd/ε₀ 
Substituting the values of the variables into the equation, we have
V = σd/ε₀
V = 5.0 × 10⁻¹² C/m² × 4.0 × 10⁻³ m/8.854 × 10⁻¹² F/m 
V = 20.0 C/m × 10⁻³/8.854 F/m
V = 2.26 × 10⁻³ Volts
V = 2.26 millivolts
So, the potential difference across the parallel plate capacitor is 2.26 millivolts
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The resistance of the sample is 
Explanation:
The relationship between resistance of a material and temperature is given by the equation

where
 is the resistance at the temperature
 is the resistance at the temperature 
 is the temperature coefficient of resistance
 is the temperature coefficient of resistance
For the sample of nickel in this problem, we have:
 when the temperature is
 when the temperature is 
While the temperature coefficient of resistance of nickel is

Therefore, the resistance of the sample when its temperature is

is

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Answer:
350 F to 100 F it take approx 87.33 min  
Explanation:
given data 
oven = 350◦F
cooling rack = 70◦F
time = 30 min 
cake = 200◦F
solution
we apply here Newtons law of cooling  
 = -k(T-Ta)
 = -k(T-Ta)
 =
 =  (T(t) -Ta)
 (T(t) -Ta) 
=  = -k(T-Ta)
 = -k(T-Ta)
-ky  = -ky
 = -ky
T(t) -Ta = (To -Ta)  T(t) = Ta+ (To -Ta)
 T(t) = Ta+ (To -Ta)   
 
put her value for time 30 min and T(t) = 200◦F and To =350◦F  and Ta = 70◦F
so here 
200 = 70 + ( 350 - 70 ) 
k = 0.025575 
so here for  T(t) = 100F 
100 = 70 + ( 350 - 70 ) 
time = 87.33 min 
so here 350 F to 100 F it take approx 87.33 min  
 
        
             
        
        
        
There is no <span>radioactive decay</span>