Suppose we connect a 10-ohm light bulb to a 6-v battery. some current flows through the battery (calculate it). now, imagine that you add a 40-ohm resistor in parallel with the light bulb. by what factor does the current through the battery increase?

The current increases by the factor 1.25                  

Explanation:

We have given that a 6 volt battery is connected to light bulb

So voltage V = 6 volt

Resistance connected R = 10 ohm

In first case

From ohm's law we know that current is given by

In second case a 40 ohm resistor is connected in parallel

So equivalent resistance will be

R = 8 ohm

So the current will be

So the factor by which current increases

So the current increases by the factor 1.25  

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.