Question

You observe that a negatively charged plastic pen repels a charged piece of invisible tape. You then observe that the same piece of tape is repelled when brought near a metal sphere. You are wearing rubber-soled shoes, and you touch the metal sphere with your hand. After you touch the metal sphere, you observe that the tape is attracted to the metal sphere. Which of the following statements could be true? Check all that apply. (1) Electrons from the sphere traveled through your body into the Earth. (2) Electrons from the sphere moved into the salt water on your skin, where they reacted with sodium ions. (3) After you touched it, the metal sphere was very nearly neutral. (4) Chloride ions from the salt water on your hand moved onto the sphere. (5) The excess negative charge from the sphere spread out all over your body. (6) Electrons from your hand moved onto the sphere. (7) Sodium ions from the salt water on your hand moved onto the sphere.

Short answer

Statement (2) is correct; Electronsfrom the sphere moved into the saltwater on your skin, where they reacted with sodium ions.

Statement (3) is correct,After you touched it, the metal sphere was very nearly neutral.

Statement (5) is correct,The excess negative charge from the sphere spread out all over your body

Statement (7) is correct, Sodium ions from the saltwater on your hand moved onto the sphere.

Step-by-step solution

Significance of the law of attraction

The law of attraction states that the unlike charges attract each other, and the like charges repel each other.

The concept of the law of attraction gives the correct statement

Determination of the correct statement

Statement (1) is incorrect as the “insulating shoe of rubber” mainly prevents the excess charges from discharging through Earth.

Statement (4) is incorrect as the sphere afterward attracts an object that carries a negative charge that indicates that the sphere is positively charged. Hence, the charge does not get transferred to the sphere.

Statement (6) is incorrect as the human body is an insulator, and hence no excess electrons move to the human body.

Statement (2) is correct as the negatively charged electrons mainly attract the sodium ions, which are positively charged. Hence, the charged sphere gets neutralized and forms sodium ions.

Statement (3) is correct because the sodium ions attract the electrons that neutralize the charged sphere, but the negative object attracts the charged sphere. Hence, a small portion of the sodium ion mainly gets transferred to the sphere.

Statement (5) is correct because the charged particle mainly works as a conductor with excess charges on the surface that eventually get equally redistributed to the human body and the sphere itself.

Statement (7) is correct as the sodium ions are positively charged, and as the sphere got attracted to the object which contained a negative charge, then the sphere has some amount of positive charge. The sodium ions also must get transferred to the sphere.

Thus, the statement (2), (3), (5), and (7) are correct.