Answer:
9.73 x 10⁻¹⁰ m
Explanation:
According to Heisenberg uncertainty principle
Uncertainty in position x uncertainty in momentum ≥ h / 4π
Δ X x Δp ≥ h / 4π
Δp = mΔV
ΔV = Uncertainty in velocity
= 2 x 10⁻⁶ x 3 / 100
= 6 x 10⁻⁸
mass m = 0.9 x 10⁻¹⁵ x 10⁻³ kg
m = 9 x 10⁻¹⁹
Δp = mΔV
= 9 x 10⁻¹⁹ x 6 x 10⁻⁸
= 54 x 10⁻²⁷
Δ X x Δp ≥ h / 4π
Δ X x 54 x 10⁻²⁷ ≥ h / 4π
Δ X = h / 4π x 1 / 54 x 10⁻²⁷
= 
= 9.73 x 10⁻¹⁰ m
Question:
A wire 2.80 m in length carries a current of 5.20 A in a region where a uniform magnetic field has a magnitude of 0.430 T. Calculate the magnitude of the magnetic force on the wire assuming the following angles between the magnetic field and the current.
(a)60 (b)90 (c)120
Answer:
(a)5.42 N (b)6.26 N (c)5.42 N
Explanation:
From the question
Length of wire (L) = 2.80 m
Current in wire (I) = 5.20 A
Magnetic field (B) = 0.430 T
Angle are different in each part.
The magnetic force is given by

So from data

Now sub parts
(a)

(b)

(c)

To solve this, we simply use trigonometry
the effective value of g along the 45° angle is
g eff = g / sin 45
g eff = g / (√2 / 2)
g eff = 2g / √2
g eff = g √2 ≈ 6.94 m/s²
Your book has applied the chain rule to produce:
dv/dt = dv/dx * dx/dt
Now, we can get dv/dx by:
1) Differentiate
x = vt, with respect to v.
dx/dv = t
Now, if we take the inverse of this, we can obtain dv/dx
dv/dx = 1/t
This is also proven by the fact that dv/dx is the change in velocity and if you multiply it by dv/dx, which is equivalent to dividing by the change in time, as we just proved, then you obtain acceleration.