When a single high-resistance (long) bulb is connected to a 1.5 volt battery, the current through the battery is about 80 milliampere. if you add another high-resistance (long) bulb in parallel, the battery current of course increases to 160 milliampere. select all of the true statements given this situation.
a. the battery is ohmic.
b. the battery is not ohmic.
c. current through the battery is proportional to δv across the battery.
d. current through the battery is not proportional to δv across the battery.
e. the battery always puts out the same current.

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.