Two metal spheres that are initially uncharged are mounted on insulating stands. A negatively charged rubber rod is brought close to, but does not make contact with sphere X. Sphere Y is then brought close to X on the side opposite to the rubber rod. Y is allowed to touch X and then is removed some distance away. The rubber rod is them moved far away from X and Y. What are the final charges on the spheres

Sphere X is positively charged while sphere Y is negatively charged

Explanation:

The method described in the given experiment is known as charging by induction. Charging by induction is a method used to charge an object without actually touching the object to any other charged object

When a negatively charged rubber rod is brought near the uncharged sphere X, charges are induced in the metal sphere. Positive charges are attracted to to the rubber rod whereas negative charges are repelled away from the rod. Since the spheres are mounted on insulated stands, the induced charges remain on the sphere. When sphere Y is made to touch sphere X, the negative charges from X flow into Y leaving it with excess negative charges.  When Y is then removed from X, the excess negative charges are then evenly distributed across the surface of Y. Finally, the rubber rod is moved far way from X leaving X with excess positive charges due to the electrons that have flowed from it into Y.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.