The electric field of a very large (essentially infinitely large) plane of charge is given by:
E = σ/(2ε₀)
E is the electric field, σ is the surface charge density, and ε₀ is the electric constant.
To determine σ:
σ = Q/A
Where Q is the total charge of the sheet and A is the sheet's area. The sheet is a square with a side length d, so A = d²:
σ = Q/d²
Make this substitution in the equation for E:
E = Q/(2ε₀d²)
We see that E is inversely proportional to the square of d:
E ∝ 1/d²
The electric field at P has some magnitude E. Now we double the side length of the sheet while keeping the same amount of charge Q distributed over the sheet. By the relationship of E with d, the electric field at P must now have a quarter of its original magnitude:

Answer:
Multiply the wavelength by the frequency.
Explanation:
The velocity of a wave is the frequency times the wavelength.
Answer:
a) Beth will reach before Alan
b)Beth has to wait 20 min for Alan to arrive
Explanation:
let 'd' be distance b/w Los Angeles and San Francisco i.e 400 mi
considering ,
Alan's speed
=50mph
Beth's speed
=60mph
->For Alan:
The time required
= d/
= 400/50 => 8h
-> For beth:
The time required
=> 6h 40m
Alan will reach at 8:00 a.m +8h = 4:00p.m.
Beth will reach at 9:00 a.m +6h 40m= 3:40p.m.
a) Beth will reach before Alan
b)Beth has to wait 20 min for Alan to arrive
The amount of metal in a closed cylindrical can that is 10 cm high and 4 cm in diameter if the metal on the top and the bottom is 0.1 cm thick and the metal on the sides is 0.05 cm thick is 8.8 cm.
The formula for calculating the volume of a cylinder is given below.
V = πr^2 h
Get the differential of the volume as shown:
dV = V/ h dh + V / r dr
V/ h = πr^2
V/ h = 2 πr h
Now, the differential becomes
dV = πr^2dh + 2πrh dr
Given the following parameters i.e. diameter and height
dh = 0.1 + 0.1 = 0.2 cm
dr = 0.05 cm
h = 10 cm
d = 4 cm
r = 2cm
Substituting the values in the above equation, we get
dV = 3.14(2)^2(0.2) + 2(3.14)(2)(10)(0.05)
dV = 2.512 + 6.28
dV = 8.792 cm
dV = 8.8 cm
If you need to learn more about diameter click here:
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