10th Class Physics Chapter 14 Short Questions with Answers Solved

Question: 1

What is electric current. In what units it is measured?

Answer: 1

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Electric Current: 'Time rate of flow of charge is called current'.

Mathematical form:

I = Delta Q/Delta t

Unit : The SI unit of current is apmpere and is presened catipa letter. A.

Question: 2

What is series combintion of resistors?

Answer: 2

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Sereis combination of resistors: When the resistors re connected end to end in such a way that threre is single path for the flow of current are saind to be connected in series. Three resistors having resistance. R1,R2 and R3 are .shown in the figure as series combintion.

Question: 3

What is Potential Differened and emf? Diffrentiate between them.

Answer: 3

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Potential Difference: The electric potential at one point can be higher, lower or equal to potentical difference at other point. ' The difference of electric potential betwen two point is called potential difference.

EMF: The potential difference developed and maintainedby source of elecrical energy is called electromotive force.

Question: 4

Differnetiate between alternating current and direct current.

Answer: 4

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Question: 5

What are Ohmic and non-Ohmic devices?

Answer: 5

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Ohicm Conductors: The conductors or materials for which Ohm\s law hold are called ohmic conductos. Thus, these conductors obey.

I inversal Delta V

It means that if we plot a graph between current "i" and potential difference "Delta V" for constant resistance, we will ge a straight line wiht slope 1/R as shwn in graph

Non- Ohmic Conductor: Th Conductors or material for which ohm's law does are called non -ohmic conductors. The graph of "i" versues"Delta V" for such materials are non-linear, as. Exampe of ohmic and non-ohmic materials.

Question: 6

State and explain Ohm's law. What are its limitations?

Answer: 6

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Question: 7

What is paralledl combination of resistors?

Answer: 7

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Question: 8

What is Kilowatt-hour

Answer: 8

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The electri meter is our homes measures energy . Electrical enery is consumed in large quantities for which joule is a very small unit. there fore, kilowatt-hour is referred. It is the amountof energy consumed by a device of power 1k W. running continuously for one hour.

E = 1 kWh

= 1000 W x 1 hr

= 1000 1.s x 3600 s

E= 3.6 x 10⁶ J

kWh is the unit for which the traiff is decided by electicity supply company.

Question: 9

DElectrical Energy and Unit of Electrical Energy.

Answer: 9

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Electrical Energy: The electrical energy lost or work done by a charge Qs going through a potential difference V, can be written

V= W/Q = E/Q

Unit of Electric Energy: The unit of energy is joule or kilowat-hour.

Question: 10

What are the hazards of electricity?

Answer: 10

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Question: 11

Define Liver Wire,Neutral Wire, Earth Wire.

Answer: 11

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Live Wire: Teh live wire carries current to the applicance at a high voltage. In fact, it is that carries the 220 V AC used by most of our home applicance.

Neutral Wire: Teh neutral wire completes the circuit and carries current away from the applicance. The neurtral wire is earthed at the local sub-station and so there is no potential difference between it and earth.

Earth Wire:

The Earth wire is a safety wire and connects the metal case of the applicance to the earh. The earth wire is for our protecntion; in case the wire makes a contat with mental casing of an applicance. When this happens, the current will pass to the earth insted of our body, thus saving us.

Question: 12

Define Electric power and unit of elecric power.

Answer: 12

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Electric Power: The time rate at which the work is done is electfic circuit is called electric power . The electric power is the work doneW in electric circuit divided by time ti.

Mathematically:

P = W/t ........... eq (1)

By definition of electric potential V

V = w/Q.............eq (2)

By defInation of current.

I = Q/t

Unit of Power: The S.I unit for electrical power is watt. A power of 1 W is said to be consumed in an electical circuit if potential differecne of 1 V, causes a current of 1 A to flow through a circuit. 1 W = 1 A x 1 V

Question: 13

Qurat-ul-Ain needs a 100 - Ohm resistor for a circuit, but she only has a bux of 300 - Ohm resistors, What can she do?

Answer: 13

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Question: 14

As water is made of atoms having protns and electrons does the water flowing through pipe carry an electric current? Explain.

Answer: 14

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Question: 15

What saftery measures are taken in household electiricity to safeguard for these hazards?

Answer: 15

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Question: 16

Explain why light bulbs almost always burn out just as they are turned on and not after they have been on for some time.

Answer: 16

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Question: 17

A car has two headilihts, when the filament in one headilgith burns out, the other headight stays on. Are the headlights connected in sereis or in parallel?

Answer: 17

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Question: 18

A number of light bulbs are connected to a single power outlet. Will they provide more illumination when connected in series or in parallel? Why?

Answer: 18

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To get more illumination from bulb they must be conneced in parallel becasue is paralll combination.

1. The potential difference across each bulb remains the same means undivided.

2- The equivalent resistane dereases in parallel combination.

3- By Switching OFF any bulb, there is no effect on the brightness of the othe rbulbs.

Question: 19

An electrician working on "live" circuits wears insulated shoes and keeps one hand behind his or her back. why?

Answer: 19

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Question: 20

Explain why is it dangerous to turn on a light bulb when you are in a bath tub?

Answer: 20

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The human body is a good conductor of electicity and curent may pass through his body when tocuhes swith because the bathtub is at the earth whihc is at zero potential. Where the switch is a high potential There fore, when a person in a bathtub he should avoid to turn ON the switch of lgith bulb because he may, get an eletric shock.

Question: 21

Why circuit breaker, fuses and switches are installed to 'live wire'?

Answer: 21

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10th Class Chapter 14 Physics Short Questions

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