What experimental evidence was provided for the nuclear model of the atom?

The nuclear model of atom was given by Rutherford. As per this model,the central part of every atom is a massive positive core, and it occupies the total mass of the atom .Around the nucleus, there are orbits in which electrons are revolving just like planets are revolving around the sun.

This evidence was provided by Rutherford's gold foil experiment.

As per this experiment, some alpha particles were deviated at an angle less than 90 degree when allowed to fall on a gold foil.Some alpha particles were deviated more than 90 degree.

One alpha particle out of 10000 particles directly retraced its path back i.e  it was deviated at angle of 180 degree.

It is so because alpha particle is positively charged. The alpha particle will be deviated if it will suffer a repulsive force. Hence, the central part of atom is positively charged. As alpha particle comes back, it means the central part is very massive.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.