Question

1. Which of the following can NOT be used to increase the current generated by an electrical generator?Select one: a. Increasing the minimum magnetic field. b. Increasing the change in the magnetic field. c. Increasing the number of coils of wire used. d. Increasing the maximum magnetic field.

2. How many protons and electrons are needed to make an atom neutral? What about the number of neutrons? How many protons and electrons are needed to make an ion of charge +1?

3. The causes of the resistive force of friction are molecular adhesion, surface roughness, and the plowing effect.

Answer 1

Question 1) answer) option b) Increasing the change in the magnetic field

Reason : in an electric generator ,

Emf produced is

E = N*B*A*w*sin(wt)

In the formula , w is angular frequency , B is the magnetic field and N is the number of turns

And current is given by

I =( Emax/R )*sin(wt)

So from the above two equations it is suggested that

Current is dependent on Bmax,Bmin and number of turns

current is dependent on max and min of magnetic field since it has sin(wt) which has minimum and maximum values from -1 to 1

Question 3) the statement is true

Reason : The causes of the friction (which is a resistive force) are molecular adhesion, surface roughness, and the plowing effect

Friction occurs due to the interlocking of the surfaces which occurs due to surface toughness and also molecular adhesion