Part A [Pg 188-191] Flashcards
What are the two kinds of charges?
1) Positive charge
2) Negative charge
What is the charge on an electron?
-1.6 x 10^-19 C
How is 1C charge defined in terms of electrons?
1C charge means a deficit of approximately 6.25 x 10^18 electrons.
What happens when two like charges interact?
Two like charges repel each other.
What happens when two unlike charges interact?
Two unlike charges attract each other.
What symbol denotes the charge on a body?
The charge on a body is denoted by the symbol q.
What is the S.I. unit of charge?
The S.I. unit of charge is coulomb (symbol C).
What are the smaller units of charge and their conversions?
1) milli-coulomb (mC) = 10^-3 C
2) micro-coulomb (µC) = 10^-6 C
3) nano-coulomb (nC) = 10^-9 C
How is the quantity of charge on a body determined?
The quantity of charge on a body is determined by the number of electrons in deficit (for positive charge) or in excess (for negative charge).
What is the relationship between charge (q) and the charge on an electron (e)?
q = n * e, where n is the integer number of electrons in deficit (for +) or excess (for -), and e is the charge on an electron.
What happens to charge in a non-conductor?
In a non-conductor (or insulator), charge is static and resides at a point where there is an excess or deficit of electrons.
In a metal the _ constitute the current
Free electrons.
True or False: A conductor is always electrically neutral.
True
What is the definition of electric current?
Current is defined as the rate of flow of charge. It is denoted by the letter I.
If a charge Q flows through a cross section normal to its direction of motion, then current I through the conductor is given by I = Q/t.
How is current measured in a circuit?
Current in a circuit is measured by an ammeter connected in series.
Ensure that the +ve marked terminal of the ammeter is towards the positive terminal of the source of current.
What is the unit of current?
The SI unit of current is the ampere (A), which is equivalent to one coulomb per second (1 A = 1 C/s).
What are the smaller units of current?
Smaller units of current are milli-ampere (mA) and micro-ampere (µA).
1 mA = 10^-3 A and 1 µA = 10^-6 A.
What constitutes current in metals?
In metals, the moving charges that constitute current are the free electrons.
What constitutes current in electrolytes and ionised gases?
In electrolytes and ionised gases, both positively charged ions (cations) and negatively charged ions (anions) are the moving charges that constitute current.
What is the relationship between charge, current, and time?
If n electrons pass through a cross section of a conductor in time t, the total charge passed is given by Q = n * e, where e is the charge of an electron.
Is current a scalar or vector quantity?
Current is a scalar quantity.
The direction of current is opposite to the direction of motion of electrons.
What is electric potential?
Electric potential at a point is measured in terms of the work done in moving a test charge from a point of zero potential to that point.
What is potential difference (P.D.)?
Potential difference is the work done in moving a unit charge from one point to another in an electric field.
What is a test charge?
A test charge is a charge of known small value that does not disturb the charges already present in that region.
