Answer:
The permittivity of rubber is 
Explanation:
From the question we are told that
The magnitude of the point charge is 
The diameter of the rubber shell is 
The Electric field inside the rubber shell is 
The radius of the rubber is mathematically evaluated as

Generally the electric field for a point is in an insulator(rubber) is mathematically represented as
Where
is the permittivity of rubber
=> 
=> 
substituting values


Answer:
T₂ = 95.56°C
Explanation:
The final resistance of a material after being heated is given by the relation:
R' = R(1 + αΔT)
where,
R' = Final Resistance = 207.4 Ω
R = Initial Resistance = 154.9 Ω
α = Temperature Coefficient of Resistance of Tungsten = 0.0045 °C⁻¹
ΔT = Change in Temperature = ?
Therefore,
207.4 Ω = 154.9 Ω[1 + (0.0045°C⁻¹)ΔT]
207.4 Ω/154.9 Ω = 1 + (0.0045°C⁻¹)ΔT
1.34 - 1 = (0.0045°C⁻¹)ΔT
ΔT = 0.34/0.0045°C⁻¹
ΔT = 75.56°C
but,
ΔT = Final Temperature - Initial Temperature
ΔT = T₂ - T₁ = T₂ - 20°C
T₂ - 20°C = 75.56°C
T₂ = 75.56°C + 20°C
<u>T₂ = 95.56°C</u>
Answer:
the angular velocity of the car is 12.568 rad/s.
Explanation:
Given;
radius of the circular track, r = 0.3 m
number of revolutions per second made by the car, ω = 2 rev/s
The angular velocity of the car in radian per second is calculated as;
From the given data, we convert the angular velocity in revolution per second to radian per second.

Therefore, the angular velocity of the car is 12.568 rad/s.