Q: Define electric current?
Ans: The rate of flow of electric charge through any cross sectional area is called electric current.
سوال :الیکٹرک کرنٹ کی تعریف کریں ؟
جواب :کسی رقبہ سے الیکٹرک چارج کے بہنے کی شرح کو الیکٹرک کرنٹ کہتے ہیں
I = Q/tQ: Define conventional current?
Unit = Ampere (A)
Ans: The current which is due to the flow of positive charge.
سوال :کنونشنل کرنٹ کی تعریف کریں ؟
.جواب :ایسا کرنٹ جو مثبت چاجز کی وجہ سے بہتا ہے
Q: Define electromotive force (emf)?
Ans: The amount of energy supplied by the battery in pushing one coulomb of charge (electrons) from its positive terminal to its negative terminal through the battery is known as the electromotive force.
سوال :
ای . ایم .ایف کی تعریف کریں ؟
جواب : ای . ایم .ایف انرجی کی اس مقدار کے برابر ہوتی ہے جو کہ بیٹری ١کولمب چارج کو اپنے پوزیٹیوٹرمینل سے نیگیٹو ٹرمینل کو منتقل کرنے کے لیے مہیا کرتی ہے
Unit = Volt (V)
Q: Define potential difference?
Ans: It determines the energy between two points of circuit which is required in moving a charge from one part to another.
Unit = Volt (V)
Q: Define Ohm's Law?
Ans: The value of current I passing through a conductor is directly proportional to the potential difference V applied across its ends, provided the temperature and the physical state of the conductor does not change.
V = IR
Q: Define limitations of Ohm's law?
Ans: Ohm's law is applicable only in case of metallic conductors when their temperature and physical state do not change.
Q: Define resistance?
Ans: The property of a substance which opposes the flow of current through it is called its resistance. It is represented by letter R. Its unit is Ohm Ω.
Ans: The unit used to measure the resistance is called ohm.
"If a current of one ampere passes through it when a potential difference of one volt is applied across its ends." It is represented by the Greek letter Ω.
Q: What are the factors upon which the resistance of conductor depend?
Ans: The resistance R of any wire is inversely proportional to its area A and is directly proportional to its length L.
R ∞ AResistance also depend upon temperature. It increases with the increase in temperature.
R ∞ 1/L
Q: Define galvanometer?
Ans: An instrument which indicates the presence of current in the circuit and it also indicates the potential difference between two points. It can measure small amount of current.
Q: Define ammeter?
Ans: An instrument which is used to measure the value of current flowing through the circuit is called ammeter. It is attached in series in the circuit.
Q: Define voltmeter?
Ans: An instrument which is used to measure the value of potential difference between two points in the circuit is called voltmeter. It is attached in parallel in the circuit.
Q: Define shunt resistance?
Ans: A resistance of low value, which is attached in parallel to the galvanometer to convert it in to ammeter. It is represented by Rs.
Q: Define Joule's law ?
Ans: Joule's law states that "the amount of heat energy generated in a resistance due to the flow of electric current is equal to the product of the square of current I, the resistance R and the time duration t".
W = I² R t
Q: Define electric power ?
Ans: The amount of energy supplied by current in unit time is known as electric power.
P = W/tThe unit of electric power is watt.
Ans: It is the amount of energy obtained by a power of one kilowatt in one hour.
amount of energy in kilowatt-hour = (watt x time in hour)/1000
Q: Differentiate between A.C and D.C ?
Ans: A current which always flows only in one direction is called direct current or d.c.
A current which change its direction again and again is called alternating current or a.c.
Q: What is neutral wire?
Ans: The wire which is at zero potential is called neutral wire.
Q: What is fuse wire or fuse?
Ans: A small wire connected in series with the live wire. It is known as fuse wire or fuse. It is used in the circuits for safety purpose.
Q: What is circuit breaker?
Ans: It is a safety device used in place of fuse. Due to any fault when the current exceeds the safety limit, then the button of the circuit breaker moves upward. Due to which the circuit breaks and the flow of the current stops in it.
Q: What is earth wire?
Ans: An additional wire is used along with the live and neutral wires. This wire is known as earth wire because its one end is connected directly to earth by means of a water pipe leading to ground or by means of an earth terminal.
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