<h3><u>Answer;</u></h3>
the north end to the south end.
<h3><u>Explanation;</u></h3>
- Magnetic field lines from a bar magnet form lines that are closed. The direction of magnetic field is taken to be outward from the North pole of the magnet and in to the South pole of the magnet.
- A magnetic field refers to the area surrounding a magnet where a force is exerted on certain objects. These lines are spread out of the north end of the magnet.
- The magnetic field lines resemble a bubble.
Answer:
Speed = 20 m/s
Explanation:
The speed of a bus is 72 km/h
The SI unit of speed is m/s
We need to convert it into m/s
We know that,
1 km = 1000 m
1 h = 3600 s
It means,
So, the speed of the bus is 20 m/s.
Answer:
a) 43.98 V
b) E = 21.37 MJ
Explanation:
Parameters given:
Length of cable = 180 km = 180000 m
Diameter of cable = 11 cm = 0.11 m
Radius = 0.11 / 2 = 0.055 m
Current, I = 135 A
a) To find the potential drop, we have to find the voltage across the wire:
V = IR
=> V = IρL / A
where R = resistance
L = length of cable
A = cross-sectional area
ρ = resistivity of the copper wire = 1.72 * 10^(-8) Ωm
Therefore:
V = (135 * 1.72 * 10^(-8) * 180000) / (π * 0.055^2)
V = 43.98 V
The potential drop across the cable is 43.98 V
b) Electrical energy is given as:
E = IVt
where t = time taken = 1 hour = 3600 s
Therefore, the energy dissipated per hour is:
E = 135 * 43.98 * 3600
E = 21.37 MJ (mega joules, 10^6)