If a cat repeatedly rubs against your cotton slacks on a dry day, the charge tra

Question

If a cat repeatedly rubs against your cotton slacks on a dry day, the charge transfer between the cat hair and the cotton can leave you with an excess charge of 2.52 µC.

(a) How many electrons are transferred between you and the cat?
electrons

You will gradually discharge via the floor, but if instead of waiting, you immediately reach toward a faucet, a painful spark can suddenly appear as your fingers near the faucet.

(b) In that spark, do electrons flow from you to the faucet or vice versa?

from you to the faucetfrom the faucet to you     

(c) Just before the spark appears, do you induce positive or negative charge in the faucet?

positivenegative     

(d) If, instead, the cat reaches a paw toward the faucet, which way do electrons flow in the resulting spark?

from the cat to the faucetfrom the faucet to the cat     

(e) If you stroke a cat with a bare hand on a dry day, you should take care not to bring your fingers near the cat's nose or you will hurt it with a spark. Considering that cat hair is an insulator, explain how the spark can appear. (Consider the following as your fingers approach the cat's nose. Select all that apply.)

The charges on your fingers and on the nose repel each other, producing a spark.The charges on your fingers and on the nose attract each other, producing a spark.The tip of the nose is charged with the opposite sign as the charge on your fingers.The tip of the nose is charged with the same sign as the charge on your fingers.

Explanation / Answer

From the given question,

(a)Excess charge= -2.52*10^-6 C

Charge of 1 electron= 1.6*10^-19 C

Number of electrons transfered= (2.52*10^-6)/(1.6*10^-19)=1.575*10^13 electrons

(b) In that spark, electrons flow from you to the faucet .

c)Just before the spark appears, you induce positive charge in the faucet.

(d) If, instead, the cat reaches a paw toward the faucet,electrons flow from the cat to the faucet in the resulting spark.

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