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Physics, Chemistry and Biology: Post your doubts here!

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There are 2 resistors in the circuit (when the switch is in position A) the 22 ohms and the 2 ohms! Both are connected in series so the total resistance will be:
Rt = R1 + R2 = 22 + 2 = 24 ohms :)

ii)
Total resistance = (R1*R2)/(R1+R2)
R1 is 22 + 2 = 24 ohms
R2 is 8 ohms

We use this formula because they are in parallel:

=(8*24)/(8+24)
= 6 ohms

-------------------
i think this ans. is wrong ... in the ms i-2 and ii- 24
 
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:LOL: It's ok :p Happens with everyone :p Like i forgot what was radiation yesterday :D

Hahaa, I've got a quick question. Could you explain the difference between an AC generator and a DC motor. (Other then the fact ones AC and the others DC :S )
 
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Anddd how to magnetise/demagnetise a magnet using a coil and different forms of current (AC/DC)
 
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Hahaa, I've got a quick question. Could you explain the difference between an AC generator and a DC motor. (Other then the fact ones AC and the others DC :S )
In an AC generator, MOTION in a MAGNETIC FIELD (due to rotation of the coil) produces CURRENT!
In a DC motor, CURRENT (probably DC) in a MAGNETIC FIELD produces MOTION!

Hope you got me :p That's the basic difference... i could say more if you want me to :)
 
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In an AC generator, MOTION in a MAGNETIC FIELD (due to rotation of the coil) produces CURRENT!
In a DC motor, CURRENT (probably DC) in a MAGNETIC FIELD produces MOTION!

Hope you got me :p That's the basic difference... i could say more if you want me to :)

Ah k yeah I understood now, thanks. What about the other question? :S
 
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Anddd how to magnetise/demagnetise a magnet using a coil and different forms of current (AC/DC)

To magnetize:

1) The stroking method:
You take a magnet and the metal you want to magnetize and stroke the magnet on it until it becomes a magnet :p

2) This is the better method: Electrical method:
You place the metal you want to magnetize in a solenoid and then pass a large DC current through it!

To demagnetize:

The most effective method is:
Place the magnet in a solenoid. Then SLOWLY WITHDRAW the magnet from the solenoid AS a large Ac current is passing through it!
 
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To magnetize:

1) The stroking method:
You take a magnet and the metal you want to magnetize and stroke the magnet on it until it becomes a magnet :p

2) This is the better method: Electrical method:
You place the metal you want to magnetize in a solenoid and then pass a large DC current through it!

To demagnetize:

The most effective method is:
Place the magnet in a solenoid. Then SLOWLY WITHDRAW the magnet from the solenoid AS a large Ac current is passing through it!

Finally an easy definition of this.
Thanks alot x)
 
Messages
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There are 2 resistors in the circuit (when the switch is in position A) the 22 ohms and the 2 ohms! Both are connected in series so the total resistance will be:
Rt = R1 + R2 = 22 + 2 = 24 ohms :)

ii)
Total resistance = (R1*R2)/(R1+R2)
R1 is 22 + 2 = 24 ohms
R2 is 8 ohms

We use this formula because they are in parallel:

=(8*24)/(8+24)
= 6 ohms

-------------------
i think this ans. is wrong ... in the ms i-2 and ii- 24
Yeah i noticed my mistake and corrected it :)
However, the answer of ii is 6 ohms
 
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DOUBTS IN SYALLABUS.... PLEASE ANSWER!!!!!!
1-adv. and disadv. for methods of production of electricity in terms of cost,reliability,scale and environmental impact
2-safety issues regarding th use of microwaves and x-rays
3-recall and use the simple electron model to distinguish betweein conductors and insulators
4-state the qualitative variation of the strength of the magnetic field over salient parts of the pattern
5-describe an experiment to show the corresponding force on beams of charged particals

PLEASE HELP!! MAY ALLAH GIVE GOOD DEEDS
 
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