Answer:
t = 1.27 x 10⁹ s
Explanation:
First, we will find the volume of the wire:
Volume = V = AL
where,
A = Cross-sectional area of wire = πr² = π(1 cm)² = π(0.01 m)² = 3.14 x 10⁻⁴ m²
L = Length of wire = 150 km = 150000 m
Therefore,
V = 47.12 m³
Now, we will find the number of electrons in the wire:
No. of electrons = n = (Electrons per unit Volume)(V)
n = (8.43 x 10²⁸ electrons/m³)(47.12 m³)
n = 3.97 x 10³⁰ electrons
Now, we will use the formula of current to find out the time taken by each electron to cross the wire:
where,
t = time = ?
I = current = 500 A
q = total charge = (n)(chareg on one electron)
q = (3.97 x 10³⁰ electrons)(1.6 x 10⁻¹⁹ C/electron)
q = 6.36 x 10¹¹ C

Therefore,
<u>t = 1.27 x 10⁹ s</u>
Answer:
ANS : .Energy spent on spraying =
Explanation:
<em>Given:</em>
- <em>Radius of mercury = 1cm initially ;</em>
- <em>split into
drops ;</em>
Thus, volume is conserved.
i.e ,

- Energy of a droplet =
Δ
Where ,
- <em>T is the surface tension </em>
- <em>ΔA is the change in area</em>
Initial energy 
Final energy 
∴ .Energy spent on spraying = 
ANS : .Energy spent on spraying =
Mike enters a revolving door that is not moving. Mike should
push at the edge of the door where it is largest distance from the pivot point
in order to produce a torque with the least amount of force. Torque is equal to
t = force x distance.
<span>The answers are --
a) wind direction
b) wind speed
e) intensity of precipitation
f) location of precipitation</span>