It would be B since it starts with the solar energy which is converted to electricity with the solar panels, which then creates mechanical energy for the fans blades to move and sound for the radio.
Hope that helps :)
It's number three on your worksheet. ;)
Answer:
U = – 0.12J
Explanation:
Given N = 10 turns, I = 5A, r = 5×10-²m
B^ = 0.05 T iˆ+ 0.3 T kˆ
Magnitude of the magnetic field vector B = √(0.05²+0.3²) = 0.304T
Area = πr² = π(5×10-²)² = 7.85×10-³m²
Magnetic moment μ = NIA
μ = 10×5×7.85×10-³ = 0.3925Am²
U = -μ•B = –0.3925×0.304 = –0.12J
The sign is negative because the magnetic moment is aligned with the magnetic field.
v = speed of car = 90 km/h
u = speed of truck = 50 km/h
d = initial separation distance = 100 m = 0.1 km
They meet at time t such that
vt = d + ut
t(v - u) = d
t = d/(v - u) = (0.1 km) / [(90 - 50) km/h] = 0.0025 hours
