An immersion heater has a thermostat to control the water temperature in a hot water tank. When the temperature of the water inside the tank reaches 58°C the thermostat switches the heater off. The thermostat switches the heater back on when the temperature of the water falls to 50°C. The graph shows how the temperature of the water inside a hot water tank changes with time. The tank is not insulated. Which of the following gives the best explanation why the temperature of the water falls at the fastest rate just after the heater switches off?

1= 26.17

2= 1.17

3=30.86

4=5.86

just took the assigment on edge

its a 5.5 n

glad that

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.