Answer:

Explanation:
From the question we are told that:
Number of battery 
Voltage source
Lamp Power
Generally the equation for Resistance is mathematically given by



Therefore


Generally the equation for Current is mathematically given by



B) It’s material moves due to convection currents.
Answer:
0.243 m/s
Explanation:
From law of conservation of motion,
mu+m'u' = V(m+m')................. Equation 1
Where m = mass of the first car, m' = mass of the second car, initial velocity of the first car, u' = initial velocity of the second car, V = Final velocity of both cars.
make V the subject of the equation
V = (mu+m'u')/(m+m')................. Equation 2
Given: m = 260000 kg, u = 0.32 m/s, m' = 52500 kg, u' = -0.14 m/s
Substitute into equation 2
V = (260000×0.32+52500×(-0.14))/(260000+52500)
V = (83200-7350)/312500
V = 75850/312500
V = 0.243 m/s
PE=mgh
180=0.5*10*h
180=5h
h=180/5=36 m